This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Anderson, K. M. Articles by Koch, W. J. Search for Related Content PubMed PubMed Citation Articles by Anderson, K. M. Articles by Koch, W. J.

(Hypertension. 1999;33:402-407.)
© 1999 American Heart Association, Inc.

Scientific Contributions

The Myocardial ß-Adrenergic System in Spontaneously Hypertensive Heart Failure (SHHF) Rats

Presented in part at the 52nd Annual Fall Conference and Scientific Sessions of the American Heart Association, sponsored by American Heart Association's Council for High Blood Pressure Research, Philadelphia, Pa, September 15–18, 1998.

Karen M. Anderson; Andrea D. Eckhart; Robert N. Willette; Walter J. Koch

From the Department of Cardiovascular Pharmacology (K.M.A., R.N.W.), SmithKline Beecham Pharmaceuticals, King of Prussia, Pa; and the Department of Surgery (A.D.E., W.J.K.), Duke University Medical Center, Durham, NC.

Correspondence to Dr Karen M. Anderson, SmithKline Beecham Pharmaceuticals, PO Box 1539, 709 Swedeland Rd, UW2510, King of Prussia, PA 19406. E-mail Karen_M_Anderson{at}SBPHRD.com

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
Abstract—Responsiveness to ß-adrenergic stimulation is reduced in the failing human myocardium. This results principally from reduced ß-adrenergic receptor (ßAR) density, elevated ß-adrenergic receptor kinase 1 (ßARK1) levels, and functional uncoupling of remaining receptors. The temporal nature of changes in the human myocardial ß-adrenergic system relative to onset of symptomatic heart failure (HF) has been difficult to discern. A relatively new model of HF, the spontaneously hypertensive heart failure (SHHF) rat spontaneously and reproducibly develops left ventricular hypertrophy (LVH) and progresses to HF, thus enabling longitudinal studies to examine the cellular and molecular bases for hypertension-induced cardiac hypertrophy and subsequent HF. The purpose of this study was to examine age-dependent changes in the ßAR system in this model. Lean male SHHF rats at 3, 7, 14, and 20 months were compared with age-matched Sprague-Dawley (SD) control rats ([C]; 4 animals/group). At all ages the SHHF rats had elevated blood pressures and left ventricular end-diastolic pressure relative to the SD control rats (P<0.05). Compared with age-matched SD control rats, LVH was evident by 3 months in SHHF rats; 20-month-old SHHF rats had significantly greater LVH compared with the other SHHF rat groups. ß-adrenergic responsiveness (maximal heart rate to isoproterenol) was reduced only in 20-month-old SHHF rats. ßARK1 protein levels and activity were elevated at 14 months (162±10% and 195±20% C, respectively), and ßARK1 protein remained elevated at 20 months (140±14% C). In contrast, G protein–coupled receptor kinase 5, a second receptor kinase in the heart, remained unchanged at all ages. ßAR density did not change with age in the SD control rats and was similar in the SHHF rats until 20 months of age when the receptor number was reduced (30±1%). These data indicate that cardiac dysfunction is coincident with reduced ßAR density. Importantly, cardiac dysfunction was preceded by elevated ßARK1 levels and activity, thus suggesting that ßARK1 may be a precipitating factor in the transition from hypertension-induced compensatory cardiac hypertrophy to HF. Furthermore, these results indicate that the SHHF rat is a powerful model for use in examination of the mechanisms involved in alterations of ß-adrenergic signaling that occur in human HF.

Key Words: hypertension, experimental • hypertrophy, cardiac • heart failure • receptors, adrenergic, beta • kinase • adenylyl cyclase • rats, inbred SHR

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
Hypertension and hypertension-induced cardiac hypertrophy are recognized risk factors for the development of heart failure (HF). The fundamental molecular mechanisms involved in the initial compensatory hypertrophic response to elevated systemic pressures and subsequent progression to HF remain largely undefined. It has been proposed that desensitization of the ß-adrenergic signaling system contributes to the progression from hypertrophy to HF.¹ Indeed, patients with chronic HF demonstrate reduced cardiac ß-adrenergic receptor (ßAR)–mediated responsiveness in the face of high circulating catecholamine levels.^{2 3 4 5 6} Evaluation of ventricular samples from patients with near-end or end-stage HF indicates that in HF there is reduced ßAR density,^{6 7 8 9} elevated levels and activity of ß-adrenergic receptor kinase 1 (ßARK1), which functionally uncouples ßARs,^{10 11 12 13} alterations in G proteins,^{7 14 15 16 17} and decreased adenylyl cyclase (AC) activity.^{18 19 20} Difficulty in obtaining serial ventricular samples from patients with HF and variability in changes in ß-adrenergic signaling in different contrived models of heart failure⁷ render it difficult to distinguish whether such changes are causally related or merely correlative with progression to symptomatic HF.

A relatively new genetic model of hypertension-induced heart failure, the spontaneously hypertensive heart failure (SHHF/Mcc-fa^cp) rat, is now commercially available. Originally derived from a cross between spontaneously hypertensive rats (SHR) and Koletsky obese rats, and then bred to SHR at the NIH (SHR-N), the colony had been maintained by McCune (Mcc designation) at the Ohio State University.²¹ These rats exhibit early-onset hypertension, and all animals develop HF. While in HF the SHHF rats exhibit numerous symptoms and biochemical changes that parallel documented changes in patients with hypertension, cardiomyopathy, and HF.^{21 22 23 24 25 26 27} Evaluation of SHHF animals at different ages should facilitate elucidation of mechanisms temporally and causally involved in the progression from stable compensatory myocardial hypertrophy to HF. Thus, the purpose of this study was to functionally and biochemically evaluate components of the ßAR signaling cascade over a wide range of ages in lean males from this unique genetic model of HF.

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Assessment of Hemodynamics and Heart Weight in the SHHF and Sprague-Dawley Rats
Lean male SHHF (n=16; Genetic Models, Inc, Indianapolis, IN) rats and Sprague-Dawley (SD; n=16; Charles River Laboratories, Raleigh, NC) rats were housed in an accredited laboratory animal facility, and all procedures were performed in accordance with the Guide for the Care and Use of Laboratory Animals (US Department of Health, Education, and Welfare, Department of Health and Human Services, NIH Publication 85-23). All procedures were approved by the Animal Care and Use Committee at SmithKline Beecham Pharmaceuticals.

In all animals, anesthesia was induced with isoflurane (4% in O₂), and a catheter was placed in the femoral vein for the administration of drugs. Isoflurane was discontinued, and anesthesia was maintained with pentobarbital (35 mg/kg, IV; with 5 mg/kg supplemental doses as needed). The right common carotid artery was exposed, and a micro-tipped pressure transducer (Millar Instruments) was inserted retrogradely for recording arterial blood pressure. The transducer was then advanced into the left ventricle to record left ventricular pressures. Left ventricular end-diastolic pressure (LVEDP) and the maximum rates of contraction (+dP/dT) and relaxation (–dP/dT) were derived from the left ventricular pressure pulse. After these ventricular recordings had been made, the pressure transducer was again withdrawn into the common carotid artery for the determination of the maximum chronotropic response and the maximum vasodepressor response elicited by isoproterenol (10 µg/kg, IV). The heart rate tachometer was triggered by the arterial pressure pulse. Each hemodynamic evaluation was completed within 30 to 40 minutes. At the termination of the functional study, the animal was euthanized, and the heart was removed. Weights were obtained for the combined left ventricle/septum (LV+S). The samples were snap-frozen in liquid nitrogen and stored at -80°C.

Determination of ßAR Density
Total ßAR density was determined using myocardial sarcolemmal membranes.²⁸ Portions of the LV+S of SD or SHHF rats were homogenized in ice-cold buffer A (25 mmol/L Tris–HCl [pH 7.5], 5 mmol/L EDTA, 5 mmol/L EGTA, 10 mg/mL leupeptin, 20 mg/mL aprotinin, and 1 mmol/L phenylmethylsulfonyl fluoride). Nuclei and tissue were separated by centrifugation at 800g for 15 minutes. The crude supernatant was then centrifuged at 20 000g for 15 minutes. Protein concentrations were determined using Bradford reagent (Pierce) on the supernatant (cytosolic fraction). Sedimented proteins (membrane fraction) were resuspended in 50 mmol/L HEPES (pH 7.3) and 5 mmol/L MgCl₂. ßAR binding was determined by incubating 25 µg of sarcolemmal membranes with a saturating concentration of [¹²⁵I]cyanopindolol and 20 mmol/L alprenolol to define nonspecific binding.²⁸

Western Blot Analysis of ßARK1 Protein Levels
Immunoblotting of ßARK1 was performed on 500 µg of protein from the left ventricular cytosolic fraction after immunoprecipitation with a monoclonal ßARK1/ßARK2 antibody as described previously.^{28 29} The ßARK1 protein was visualized with a monoclonal antibody raised against an epitope within the carboxyl terminus of ßARK1 and chemiluminescent detection of anti-mouse IgG conjugated with horseradish peroxidase (Renaissance; Amersham). To detect G protein–coupled receptor kinase 5 (GRK5), 30 µg of protein from the LV+S membrane fraction was loaded on a 12% Tris-glycine gel. GRK5 was visualized with a monoclonal antibody to the carboxy-terminus and chemiluminescent detection of anti-mouse IgG.³⁰

Evaluation of ßARK1 Activity
ßARK1 activity was determined in LV+S cytosolic fractions with rhodopsin-enriched rod outer segment membranes as an in vitro substrate and [-³²P]ATP as described previously.²⁸ [³²P] incorporation into rhodopsin was quantified by using a Molecular Dynamics PhosphorImager.²⁸

Determination of AC Activity
AC activity was determined on 20 µg of left ventricular sarcolemmal membranes in triplicate.²⁸ Membranes were incubated for 15 minutes at 37°C with [-³²P]ATP under basal conditions or after stimulation with 10^–4 mol/L isoproterenol to stimulate ßARs or 10 mmol/L sodium fluoride (NaF) to activate all G proteins. cAMP was quantified as described previously.²⁸

	Results

Top Abstract Introduction Methods Results Discussion References

 
Assessment of Hemodynamic Parameters and Cardiac Mass
The SHHF rats were significantly hypertensive relative to the SD control rats as early as 3 months of age (mean arterial pressure, 193.3±4.0 and 111.3±4.6 mm Hg, for SHHF and SD rats, respectively; mean±SEM; n=4 per strain). As shown in Figure 1, mean arterial, systolic, and diastolic pressures remained stable and elevated in SHHF rats until 20 months of age when mean and systolic pressures fell significantly. Body weights were significantly greater in SD control rats at all ages; although SD rat and SHHF rat body weights increased between 3 and 7 months, body weight did not change in the SD or SHHF rats between 7 and 20 months (SD: 562±13.92 versus 575±14.45 g; SHHF: 435±8.42 versus 437.5±2.5 g, 20 months versus 7 months). LV mass was increased as early as 3 months in the SHHF rats and increased more with age (Figure 2), reflecting hypertension-induced cardiac hypertrophy and suggesting that these animals become hypertensive much earlier than 3 months. As shown in Figure 3A, the maximum rate of contraction [(+) dP/dT] is significantly depressed at 20 months, and this is preceded by a reduced lusitropy [(–) dP/dT]. Relative to age-matched SD rats, LVEDP was elevated in SHHF rats at 3 months (14.2±2.8 versus 5.9±4.0 mm Hg, mean±SEM, n=4/group) and progressively increased with age (Figure 3B). Cardiac responsiveness to infused isoproterenol was diminished in 20-month-old SHHF rats as demonstrated by a significantly depressed chronotropic response (Figure 4). Isoproterenol decreased blood pressure by 35.2±1.99 mm Hg in all SHHF rats with no difference among the 4 age groups.

View larger version (28K): [in this window] [in a new window]   Figure 1. Systolic, diastolic, and mean arterial pressures of anesthetized SHHF rats. Results from 4 age groups (3, 6, 14, and 20 months) were compared (n=4 animals per group). *P<0.05 indicates a significant difference when compared with the 6-month group (ANOVA and Bonferroni test).

View larger version (21K): [in this window] [in a new window]   Figure 2. Left ventricular weights from SHHF rats and age-matched SD control rats. After removing the atria and right free wall, the weight of the left ventricular free wall and ventricular septum (LV+S) was obtained as an index of LVH. The data were normalized to body weight and are expressed as the ratio of LV+S per 100 g body weight. The SD rats showed no evidence of LVH at any age. Relative to the age-matched SD control rats, the SHHF rats had significantly greater LV+S mass at all ages, with the most pronounced difference at 20 months. *P<0.05, 2-tailed t-test. Comparisons among the SHHF rat groups indicated significantly increased LVH at 20 months (P<0.05; ANOVA and Bonferroni test).

View larger version (19K): [in this window] [in a new window]   Figure 3. Left ventricular (LV) hemodynamic parameters in anesthetized rats(SHHF). A, The rates of contraction (+dP/dT) and relaxation (–dP/dT) were significantly depressed in the older age groups. B, Elevations in LVEDP were linearly correlated with increasing age. n=4 animals per group. *P<0.05 (ANOVA and Bonferroni test).

View larger version (19K): [in this window] [in a new window]   Figure 4. ß-Adrenoceptor reactivity in anesthetized SHHF rats. The maximum chronotropic response elicited by isoproterenol (10 µg/kg, IV). Results from 4 age groups (3, 6, 14, and 20 months) were compared (n=4 animals per group). *P<0.05 (ANOVA and Bonferroni test).

Myocardial ßAR Signaling Properties
Biochemical and molecular biological approaches were used to determine whether abnormalities in ßAR signaling contributed to the depressed cardiac function in older SHHF rats and to examine the chronology of any noted changes in ßAR signaling relative to the observed onset of cardiac dysfunction in this genetic model of heart failure. ßAR density for control SD rats was 34.6±3.4 fmol/mg protein and was unchanged with age. ßAR density progressively declined in SHHF rats, and at 20 months of age was significantly attenuated (Figure 5). ßAR affinity was unchanged with age or between control and SHHF rat groups.

View larger version (11K): [in this window] [in a new window]   Figure 5. Change in left ventricular ßAR density in SHHF rats compared with SD control rats. ßAR binding was determined in control and SHHF rats. ßAR density did not change with age in the SD control animals (data not shown). Data from SHHF rats are expressed as a percentage of the age-matched control values. n=4 for each of control and SHHF rats at each age group. ßAR density was significantly depressed in the 20-month-old SHHF animals. *P<0.05 vs control, 2-tailed t-test.

We assessed AC activity to examine the signaling properties of the ßARs in control versus SHHF rats. Basal AC was not different between SD and SHHF rats (data not shown), and there was no difference with age or between control SD (137.3±17.3 pmol · mg^–1 · min^–1, n=16) and SHHF (133.1±18.1 pmol · mg^–1 · min^–1, n=16) rats for NaF-stimulated AC activity. However, isoproterenol-stimulated AC activity was significantly depressed at 14 (24%) and 20 (36%) months in the SHHF rats (Figure 6). Therefore, SHHF rats concomitantly exhibit age-dependent decreased ßAR density and ßAR-mediated signaling.

View larger version (19K): [in this window] [in a new window]   Figure 6. Isoproterenol (ISO)-stimulated AC activity in control vs SHHF rats. cAMP production expressed as a percentage of NaF values after 10–4 mol/L isoproterenol stimulation. Data are expressed as mean±SEM; n=4 animals per group. *P<0.05 1-tailed t-test (14 months); 2-tailed t-test (20 months).

Expression and Activity of ßARK1
ß-adrenergic receptor kinase (ßARK1 or G protein–coupled receptor kinase 2 [GRK2]) is a prototypical member of a family of at least 6 serine/threonine kinases known as the GRKs that specifically phosphorylate agonist-occupied G protein–coupled receptors leading to desensitization.^{12 13 28} ßARK1 is a critical in vivo modulator of ßAR-mediated myocardial function.²⁸ Human HF is associated with alterations in ßAR signaling, including downregulation and desensitization of ßARs.^{6 7 8 9 10 11 12 13} To test the hypothesis that ßARK1 is involved in the decreased ßAR number (Figure 5) and depressed signaling (Figure 6) in SHHF rats, expression and activity of the myocardial GRKs ßARK1 and GRK5 were examined. Similar to what we have observed before, neither ßARK1 expression nor activity changed with age in the control rats.³¹ However, in the SHHF rats, ßARK1 expression progressively increased with age and was significantly greater than that in control rats at both 14 (63±10%, n=4, P=0.0008) and 20 (40±14%, n=4, P=0.0289) months (Figure 7A).

View larger version (19K): [in this window] [in a new window]   Figure 7. A, ßARK1 expression in left ventricle of SHHF rat hearts compared with age-matched SD control animals. Above, Representative autoradiogram of ßARK1 immunodetection (Western blot analysis) in SHHF rats 3 to 20 months of age. Intensity of the immunoreactive band from a 3-month-old SD control rat is included as a reference. ßARK1 protein levels did not change with age in the SD control animals (see text). Below, histogram demonstrating significantly elevated ßARK1 protein in SHHF rat hearts at 14 and 20 months. Data represent the percentage increase relative to the age-matched SD control rats and are expressed as mean±SEM (n=4 for control and SHHF rats at each age). *P<0.05, 2-tailed t-test. **P<0.01, 2-tailed t-test. B, Histogram of ßARK1 activity in left ventricle of SHHF rat hearts compared to age-matched control (SD) rats. ßARK1 activity was measured by phosphorylation in vitro of the GRK substrate rhodopsin-enriched rod outer segment membranes (see "Methods"). Data represent percentage of age-matched control rats and are expressed as mean±SEM (n=4 for control and SHHF rats at each age). *P<0.05, 2-tailed t-test.

Enzymatic activity of soluble ßARK1 on the G protein–coupled receptor substrate rhodopsin (see "Methods") was measured in cytosolic extracts. ßARK1 activity was significantly increased in SHHF rats by 14 months (95±36%, n=4, P=0.038; Figure 7B). Unlike ßARK1, there were no changes with age or between control and SHHF rat groups in membrane-bound GRK5 expression (data not shown).

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
It is well established that in human heart failure compromised cardiac function is associated with alterations in the ß-adrenergic signaling cascade including reduced myocardial ßAR density, increased ßARK1, and decreased AC activity.^{6 7 8 9 10 11 12 13 18 19 20} The purpose of the present study was to characterize in vivo cardiac adrenergic responsiveness with increasing age in a unique genetic model of spontaneous hypertension-induced myocardial hypertrophy and HF (the SHHF/Mcc-fa^cp rat) and to examine components of the ßAR signaling cascade in the same animals. SHHF rats were studied at 3, 7, 14, and 20 months. Relative to age-matched SD control rats, SHHF rats had significantly elevated blood pressure, elevated LVEDP, and LVH as early as 3 months of age. Compared with age-matched SD rats, resting blood pressure was elevated in all SHHF rat groups; compared with 6-month-old SHHF rats, systolic and mean arterial pressures were significantly decreased in 20-month-old SHHF rats. This was coincident with depressed cardiac contractility [(+) dP/dT] and was preceded by depressed lusitropy [(–) dP/dT]. Cardiac sensitivity to isoproterenol was significantly attenuated in 20-month-old SHHF rats. This was coincident with reduced ßAR density and was preceded by elevated ßARK levels and activity. Reduced AC activity at 14 and 20 months was consistent with elevated ßARK at these ages.

The onset of overt HF in the SHHF rats varies with the phenotype of the rat, ranging from 10 to 13 months (obese males) to approximately 24 months in lean females.²¹ The lean males used in this study reportedly exhibit symptoms of overt HF at 14 to 18 months.²¹ Documented symptoms and biochemical changes that occur in SHHF rats and that parallel human HF include dyspnea, cyanosis, orthopnea, subcutaneous edema, ascites, hepatomegaly and congestion, pleural effusion, lethargy, piloerection, increased urinary excretion, cachexia, weight loss, reversal of contractile proteins (myosin and actin) to fetal forms, elevated atrial natriuretic peptide, elevated plasma renin activity, elevated circulating norepinephrine, and reduced enzymes involved in fatty acid oxidation.^{21 22 23 24 25 26 27} We monitored our animals closely via daily visual examination. The 20-month-old lean males used in this study were included on the basis of their exhibition of initial overt symptoms of HF, specifically increased respiratory rate and effort. It was somewhat surprising that they did not exhibit overt HF until 20 months of age, but it is possible this study was performed on homozygote animals because they tend to live longer than the lean males that are heterozygote for the corpulent gene.³²

The fundamental molecular mechanisms that contribute to progression in humans from compensatory hypertension-induced cardiac hypertrophy to cardiac dysfunction are poorly understood, but it has been proposed that altered ßAR signaling plays a role.¹ Consistent with data from left ventricular samples of patients with HF,^{6 7 8 9} the present study demonstrates that SHHF rats with compromised cardiac function have reduced ßAR density. Importantly, the in vivo functional changes and the reduction in ßARs observed in the SHHF rats are preceded by an increase in the level and activity of ßARK1. Given that the 20-month-old SHHF rats had just begun to show overt symptoms of HF, elevation of ßARK1 preceded symptomatic HF by at least 6 months. Thus, these data suggest that alterations in ßARK1 may represent a key trigger to the initiation of HF and support the hypothesis that ßARK1 is a good target for development of a therapeutic agent for treatment of HF.³³

The present study is the first to examine the in vivo myocardial response of SHHF rats to direct ß-adrenergic stimulation, and it is the first to document definitive changes in components of the ß-adrenergic system in the intact myocardium of this model. Gomez et al²⁴ reported that myocytes isolated from 17- to 18-month-old lean male SHHF rats in overt HF and from hypertrophic hearts of hypertensive Dahl salt-sensitive rats had diminished sarcoplasmic reticulum calcium release in response to electrical depolarization. Interestingly, ßAR stimulation via isoproterenol overcame this deficit in the myocytes from Dahl salt-sensitive rats but produced virtually no response in the myocytes from the animals in HF, perhaps, the authors speculate, because of downregulation of the cardiac ßARs. The data presented herein from 20-month-old lean males demonstrating initial symptoms of overt HF support their conclusion. Consistent with our results in intact myocardium, SHHF myocytes from 6-month-old obese female animals retain their full complement of ßARs relative to myocytes from 4-month-old SD rats.²⁵ However, reduced isoproterenol-stimulated cAMP production by the cells suggested a decrease in AC activity by 6 months of age.²⁵ Exciting preliminary data from our laboratories confirm that, compared with age-matched SD rats, basal cAMP production and isoproterenol-stimulated cAMP production are significantly attenuated in myocytes isolated from 20-month-old lean males and demonstrate that this can be reversed to near normal by adenoviral-mediated expression of a ßARK inhibitor, the ßARKct, a peptide encoding the carboxy-terminus of ßARK1.^{28 34}

To summarize, lean male SHHF rats at the initial stages of overt HF have reduced chronotropic response to ß-adrenergic stimulation. This in vivo manifestation of cardiac dysfunction is coincident with reduced ßAR density and, importantly, preceded by elevated ßARK1 levels and activity. Thus, the data are concordant with the hypothesis that elevated ßARK1 may be an important precipitating factor in the transition from hypertension-induced compensatory hypertrophy to HF. Furthermore, these results provide additional data that strengthen the relevance of the SHHF rat model to the study of human HF.

	Footnotes

 
Drs Anderson and Eckhart were equal contributors to this work.

Received September 18, 1998; first decision October 15, 1998; accepted November 4, 1998.

	References

Top Abstract Introduction Methods Results Discussion References

 

1. Castellano M, Böhm M. The cardiac ß-adrenoceptor-mediated signaling pathway and its alterations in hypertensive heart disease. Hypertension. 1997;29:715–722.[Abstract/Free Full Text]
2. Ginsburg R, Bristow MR, Billingham ME, Stinson EB, Schroeder JS, Harrison DC. Study of the normal and failing isolated human heart: decreased response of failing heart to isoproterenol. Am Heart J. 1983;106:535–540.[Medline] [Order article via Infotrieve]
3. Steinfath M, Danielson W, von der Leyden H, Mende U, Meyer W, Neumann J, Nose M, Reich T, Schmitz W, Scholz H. Reduced ₁- and ß₂-adrenoceptor-mediated positive inotropic effects in human end-stage heart failure. Br J Pharmacol. 1992;105:463–469.[Medline] [Order article via Infotrieve]
4. Colucci W, Denniss AR, Leatherman GF, Quigg RJ, Ludmer PL, Marsh JD, Gauthier DF. Intracoronary infusion of dobutamine to patients with and without severe congestive heart failure: dose-response relationships, correlation with circulating catecholamines, and effect of phosphodiesterase inhibition. J Clin Invest. 1988;81:1103–1110.
5. Colucci WS, Ribeiro JP, Rocco MB, Quigg RJ, Creager MA, Marsh JD, Gauthier DF, Hartley LH. Impaired chronotropic response to exercise in patients with congestive heart failure: role of postsynaptic beta-adrenergic desensitization. Circulation. 1989;80:314–323.[Abstract/Free Full Text]
6. Bristow MR, Ginsburg R, Minobe W, Cubicciotti RS, Sageman WS, Lurie K, Billingham ME, Harrison DC, Stinson EB. Decreased catecholamine sensitivity and ß-adrenergic-receptor density in failing human hearts. N Engl J Med. 1982;307:205–211.[Abstract]
7. Gopalakrishnan M, Triggle DJ. The regulation of receptors, ion channels, and G proteins in congestive heart failure. Cardiovasc Drug Rev. 1990;8:255–302.
8. Ungerer M, Bohm M, Elce JS, Erdmann E, Lohse MJ. Altered expression of ß-adrenergic receptor kinase and ß1-adrenergic receptors in the failing human heart. Circulation. 1993;87:454–463.[Abstract/Free Full Text]
9. Brodde O-E. ß-Adrenergic receptors in failing human myocardium. Basic Res Cardiol. 1993;91:35–40.
10. Ungerer M, Parruti G, Bohm M, Puzicha M, DeBlasi A, Erdmann E, Lohse MJ. Expression of ß-arrestins and ß-adrenergic receptor kinases in the failing human heart. Circ Res. 1994;74:206–213.[Abstract/Free Full Text]
11. Lohse MJ. G-protein-coupled receptor kinases and the heart. Trends Cardiovasc Med. 1995;5:63–68.
12. Inglese J, Freedman NJ, Koch WJ, Lefkowitz RJ. Structure and mechanism of the G protein-coupled receptor kinases. J Biol Chem. 1993;268:23735–23738.[Free Full Text]
13. Freedman NJ, Liggett SB, Drachman DE, Pei G, Caron MG, Lefkowitz RJ. Phosphorylation and desensitization of the human ß₁-adrenergic receptor: involvement of G protein-coupled receptor kinases and cAMP-dependent protein kinase. J Biol Chem. 1995;270:17953–17961.[Abstract/Free Full Text]
14. Böhm M, Eschenhagen T, Gierschik P, Larisch K, Lensche H, Mende U, Schmitz W, Schnabel P, Scholz H, Steinfath M, Erdmann E. Radioimmunochemical quantification of Gi in right and left ventricles from patients with ischemic and dilated cardiomyopathy and predominant left ventricular failure. J Mol Cell Cardiol. 1994;26:133–149.[Medline] [Order article via Infotrieve]
15. Brown LA, Harding SE. The effect of pertussis toxin on ß-adrenoceptor responses in isolated cardiac myocytes from noradrenaline-treated guinea-pigs and patients with cardiac failure. Br J Pharmacol. 1992;106:115–122.[Medline] [Order article via Infotrieve]
16. Feldman AM, Cates AE, Veazy WB, Hershberger RE, Bristow MR, Baughman KL, Baumgartner WA, Van Dop C. Increase of the 40,000-mol wt pertussis toxin substrate (G protein) in the failing human heart. J Clin Invest. 1988;82:189–197.
17. Neumann J, Schmitz W, Scholz H, von Meyerinck L, Doring V, Kalmer P. Increase in myocardial G_i proteins in heart failure. Lancet. 1988;2:936–937.[Medline] [Order article via Infotrieve]
18. Bristow MR, Hershberger RE, Port JD, Minobe W, Rasmussen R. Beta 1- and beta 2-adrenergic receptor-mediated adenylate cyclase stimulation in nonfailing and failing human ventricular myocardium. Mol Pharmacol. 1989;35:295–303.[Abstract]
19. Feldman MD, Copelas L, Gwathmey JK, Phillips P, Warren SE, Schoen FJ, Grossman W, Morgan JP. Deficient production of cAMP: pharmacologic evidence of an important cause of contractile dysfunction in patients with end-stage heart failure. Circulation. 1987;75:331–339.[Abstract/Free Full Text]
20. Denniss AR, Marsh JD, Quigg RJ, Gordon JB, Colucci WS. Beta-adrenergic receptor number and adenylate cyclase function in denervated transplanted and cardiomyopathic human hearts. Circulation. 1989;79:1028–1034.[Abstract/Free Full Text]
21. McCune SA, Park S, Radin MJ, Jurin JJ. The SHHF/Mcc-fa^cp: a genetic model of congestive heart failure. In: PK Singal, IMC Dixon, RE Beamish, NS Dhalla, eds. Mechanisms of Heart Failure. Boston, MA: Kluwer Academic Publishers; 1995:91–106.
22. Holycross BJ, Summers BM, Dunn RB, McCune SA. Plasma renin activity in heart failure-prone SHHF/Mcc-fa^cp rats. Am J Physiol. 1997;273(Heart Circ Physiol. 42):H228–H233.
23. Haas GJ, McCune SA, Brown DM, Cody RJ. Echocardiographic characterization of left ventricular adaptation in a genetically determined heart failure rat model. Am Heart J. 1995;130:806–811.[Medline] [Order article via Infotrieve]
24. Gomez AM, Valdiva HH, Cheng H, Lederer MR, Santana LF, Cannell MB, McCune SA, Altschuld RA, Lederer WJ. Defective excitation-contraction coupling in experimental cardiac hypertrophy and heart failure. Science. 1997;276:800–806.[Abstract/Free Full Text]
25. Hohl CM, Hu B, Fertel RH, Russell JC, McCune SA, Altshuld RA. Effects of obesity and hypertension on ventricular myocytes: comparison of cells from adults SHHF/Mcc-cp and JCR:LA-cp rats. Cardiovasc Res. 1993;27:238–242.[Abstract/Free Full Text]
26. Gerdes AM, Onodera T, Wang A, McCune SA. Myocyte remodeling during the progression to failure in rats with hypertension. Hypertension. 1996;28:609–614.[Abstract/Free Full Text]
27. Sack MN, Rader TA, Park S, Bastin J, McCune SA, Kelly DP. Fatty acid oxidation enzyme gene expression is downregulated in the failing heart. Circulation. 1996;94:2837–2842.[Abstract/Free Full Text]
28. Koch WJ, Rockman HA, Samama P, Hamilton RA, Bond RA, Milano CA, Lefkowitz RJ. Cardiac function in mice overexpressing the ß-adrenergic receptor kinase or an ßARK inhibitor. Science. 1995;268:1350–1353.[Abstract/Free Full Text]
29. Choi D-J, Koch WJ, Hunter JJ, Rockman HA. Mechanism of ß-adrenergic receptor desensitization in cardiac hypertrophy is increased ß-adrenergic receptor kinase. J Biol Chem. 1997;272:17223–17229.[Abstract/Free Full Text]
30. Rockman HA, Choi DJ, Rahman NU, Akhter SA, Lefkowitz RJ, Koch WJ. Receptor-specific in vivo desensitization by the G protein-coupled receptor kinase-5 in transgenic mice. Proc Natl Acad Sci U S A. 1996;93:9954–9959.[Abstract/Free Full Text]
31. Xiao R-P, Tomhave ED, Ji X, Boluyt M, Cheng H, Lakatta EG, Koch WJ. Age-associated reductions in cardiac ß₁- and ß₂-adrenergic responses without changes in inhibitory G proteins or receptor kinases. J Clin Invest. 1998;101:1273–1282.[Medline] [Order article via Infotrieve]
32. McCune SA, Radin MJ, Jenkins JE, Chu Y-Y, Park S, Peterson RG. SHHF/Mcc-fa^cp rat model: effects of gender and genotype on age of expression of metabolic complications and congestive heart failure and on response to drug therapy. In: EE Shafrir, ed. Lessons from Animal Diabetes. London, UK: Smith-Gordon; 1995:255–270.
33. Lefkowitz RJ. G-protein-coupled receptors and receptor kinases: from molecular biology to potential therapeutic applications. Nat Biotechnol. 1996;14:283–286.[Medline] [Order article via Infotrieve]
34. Eckhart AD, Anderson KM, Griswold MC, Rockman HA, Koch WJ. Adenoviral-mediated gene transfer of a ß-adrenergic receptor kinase inhibitor reverses functional uncoupling in failing cardiomyocytes isolated from SHHF rats. Circulation. 1998;98(suppl I):I-806. Abstract.

This article has been cited by other articles:

				L. E. Vinge, P. W. Raake, and W. J. Koch Gene Therapy in Heart Failure Circ. Res., June 20, 2008; 102(12): 1458 - 1470. [Abstract] [Full Text] [PDF]

				K. J. Kelly, P. Wu, C. E. Patterson, C. Temm, and J. H. Dominguez LOX-1 and inflammation: a new mechanism for renal injury in obesity and diabetes Am J Physiol Renal Physiol, May 1, 2008; 294(5): F1136 - F1145. [Abstract] [Full Text] [PDF]

				J. H. Dominguez, J. L. Mehta, D. Li, P. Wu, K. J. Kelly, C. S. Packer, C. Temm, E. Goss, L. Cheng, S. Zhang, et al. Anti-LOX-1 therapy in rats with diabetes and dyslipidemia: ablation of renal vascular and epithelial manifestations Am J Physiol Renal Physiol, January 1, 2008; 294(1): F110 - F119. [Abstract] [Full Text] [PDF]

				P. Penela, C. Murga, C. Ribas, A. S. Tutor, S. Peregrin, and F. Mayor Jr. Mechanisms of regulation of G protein-coupled receptor kinases (GRKs) and cardiovascular disease Cardiovasc Res, January 1, 2006; 69(1): 46 - 56. [Abstract] [Full Text] [PDF]

				G. Iaccarino, E. Barbato, E. Cipolletta, V. De Amicis, K. B. Margulies, D. Leosco, B. Trimarco, and W. J. Koch Elevated myocardial and lymphocyte GRK2 expression and activity in human heart failure Eur. Heart J., September 1, 2005; 26(17): 1752 - 1758. [Abstract] [Full Text] [PDF]

				X. Wang, E. Sentex, H. K. Saini, D. Chapman, and N. S. Dhalla Upregulation of {beta}-adrenergic receptors in heart failure due to volume overload Am J Physiol Heart Circ Physiol, July 1, 2005; 289(1): H151 - H159. [Abstract] [Full Text] [PDF]

				S. M. Emani, A. S. Shah, M. K. Bowman, D. C. White, S. Emani, D. D. Glower, and W. J. Koch Right ventricular targeted gene transfer of a {beta}-adrenergic receptor kinase inhibitor improves ventricular performance after pulmonary artery banding J. Thorac. Cardiovasc. Surg., March 1, 2004; 127(3): 787 - 793. [Abstract] [Full Text] [PDF]

				J. G. Dobson, J. Fray, J. L. Leonard, and R. E. Pratt Molecular mechanisms of reduced {beta}-adrenergic signaling in the aged heart as revealed by genomic profiling Physiol Genomics, October 17, 2003; 15(2): 142 - 147. [Abstract] [Full Text] [PDF]

				R.-P. Xiao, S.-J. Zhang, K. Chakir, P. Avdonin, W. Zhu, R. A. Bond, C. W. Balke, E. G. Lakatta, and H. Cheng Enhanced Gi Signaling Selectively Negates {beta}2-Adrenergic Receptor (AR)- but Not {beta}1-AR-Mediated Positive Inotropic Effect in Myocytes From Failing Rat Hearts Circulation, September 30, 2003; 108(13): 1633 - 1639. [Abstract] [Full Text] [PDF]

				J. A. Hata and W. J. Koch Phosphorylation of G Protein-Coupled Receptors: GPCR Kinases in Heart Disease Mol. Interv., August 1, 2003; 3(5): 264 - 272. [Abstract] [Full Text] [PDF]

				R. Kacimi and A. M. Gerdes Alterations in G Protein and MAP Kinase Signaling Pathways During Cardiac Remodeling in Hypertension and Heart Failure Hypertension, April 1, 2003; 41(4): 968 - 977. [Abstract] [Full Text] [PDF]

				I. Tabbi-Anneni, C. Helies-Toussaint, D. Morin, A. Bescond-Jacquet, A. Lucien, and A. Grynberg Prevention of Heart Failure in Rats by Trimetazidine Treatment: A Consequence of Accelerated Phospholipid Turnover? J. Pharmacol. Exp. Ther., March 1, 2003; 304(3): 1003 - 1009. [Abstract] [Full Text] [PDF]

				N. Spyrou, S. D. Rosen, F. Fath-Ordoubadi, R. Jagathesan, R. Foale, J. S. Kooner, and P. G. Camici Myocardial beta-adrenoceptor densityone month after acute myocardial infarctionpredicts left ventricular volumes at six months J. Am. Coll. Cardiol., October 2, 2002; 40(7): 1216 - 1224. [Abstract] [Full Text] [PDF]

				X. P. Yi, A. M. Gerdes, and F. Li Myocyte Redistribution of GRK2 and GRK5 in Hypertensive, Heart-Failure-Prone Rats Hypertension, June 1, 2002; 39(6): 1058 - 1063. [Abstract] [Full Text] [PDF]

				A. D. Eckhart, T. Ozaki, H. Tevaearai, H. A. Rockman, and W. J. Koch Vascular-Targeted Overexpression of G Protein-Coupled Receptor Kinase-2 in Transgenic Mice Attenuates beta -Adrenergic Receptor Signaling and Increases Resting Blood Pressure Mol. Pharmacol., April 1, 2002; 61(4): 749 - 758. [Abstract] [Full Text] [PDF]

				B Swynghedauw and D Charlemagne What is wrong with positive inotropic drugs? Lessons from basic science and clinical trials Eur. Heart J. Suppl., April 1, 2002; 4(suppl_D): D43 - D49. [Abstract] [PDF]

				K. Leineweber, I. Heinroth-Hoffmann, K. Ponicke, G. Abraham, B. Osten, and O.-E. Brodde Cardiac {beta}-Adrenoceptor Desensitization Due to Increased {beta}-Adrenoceptor Kinase Activity in Chronic Uremia J. Am. Soc. Nephrol., January 1, 2002; 13(1): 117 - 124. [Abstract] [Full Text] [PDF]

				L. E. Vinge, E. Oie, Y. Andersson, H. K. Grogaard, G. O. Andersen, and H. Attramadal Myocardial distribution and regulation of GRK and beta -arrestin isoforms in congestive heart failure in rats Am J Physiol Heart Circ Physiol, December 1, 2001; 281(6): H2490 - H2499. [Abstract] [Full Text] [PDF]

				S. M. Emani, A. S. Shah, D. C. White, D. D. Glower, and W. J. Koch Right ventricular gene therapy with a {beta}-adrenergic receptor kinase inhibitor improves survival after pulmonary artery banding Ann. Thorac. Surg., November 1, 2001; 72(5): 1657 - 1661. [Abstract] [Full Text] [PDF]

				G. Iaccarino, J. R. Keys, A. Rapacciuolo, K. F. Shotwell, R. J. Lefkowitz, H. A. Rockman, and W. J. Koch Regulation of myocardial {beta}ARK1 expression in catecholamine-induced cardiac hypertrophy in transgenic mice overexpressing {alpha}1B-adrenergic receptors J. Am. Coll. Cardiol., August 1, 2001; 38(2): 534 - 540. [Abstract] [Full Text] [PDF]

				G. Iaccarino, E. Barbato, E. Cipolleta, A. Esposito, A. Fiorillo, W. J. Koch, and B. Trimarco Cardiac {beta}ARK1 Upregulation Induced by Chronic Salt Deprivation in Rats Hypertension, August 1, 2001; 38(2): 255 - 260. [Abstract] [Full Text] [PDF]

				C.-E. Laurent, R. Cardinal, G. Rousseau, M. Vermeulen, C. Bouchard, M. Wilkinson, J. A. Armour, and M. Bouvier Functional desensitization to isoproterenol without reducing cAMP production in canine failing cardiocytes Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2001; 280(2): R355 - R364. [Abstract] [Full Text] [PDF]

				K. Nagata, C. Communal, C. C. Lim, M. Jain, T. M. Suter, F. R. Eberli, N. Satoh, W. S. Colucci, C. S. Apstein, and R. Liao Altered beta -adrenergic signal transduction in nonfailing hypertrophied myocytes from Dahl salt-sensitive rats Am J Physiol Heart Circ Physiol, November 1, 2000; 279(5): H2502 - H2508. [Abstract] [Full Text] [PDF]

D. C. White, J. A. Hata, A. S. Shah, D. D. Glower, R. J. Lefkowitz, and W. J. Koch Preservation of myocardial beta -adrenergic receptor signaling delays the development of heart failure after myocardial infarction PNAS, May 9, 2000; 97(10): 5428 - 5433. [Abstract] [Full Text] [PDF]