(Hypertension. 1996;27:449-455.)
© 1996 American Heart Association, Inc.
Articles |
Localization of 
2A- and 2B-Adrenergic Receptor Subtypes in Brain
From the Hypertension and Atherosclerosis Section of the Department of Medicine and the Department of Anatomy and Neurobiology (D.L.R.), Boston (Mass) University School of Medicine.
Correspondence to Haralambos Gavras, MD, Hypertension and Atherosclerosis Section, Boston University School of Medicine, 80 E Concord St, Boston, MA 02118.
 |
Abstract |
|---|
 Top Abstract IntroductionMethods Results Discussion References |
|---|
Abstract Recent studies have shown that all three subtypes of
2-adrenergic receptor (2-AR) are found in
brain. The purpose of this study was to map the subtype localization of
the 2A- and 2B-ARs in brain structures.
RNase protection shows that both the 2A- and
2B-ARs are detectable in cortex, cerebellum,
pons-medulla, and hypothalamus. We tested probes derived from the
2A- and 2B-AR cDNAs on cell lines that
express each of the 2-AR subtypes to establish the
subtype specificity of these probes for in situ hybridization. Then we
used the 2A- and 2B-AR probes for in situ
hybridization on sagittal and coronal sections of rat brain. Both
2A and 2B mRNA were detected throughout
the brain. Overall, there appears to be a greater expression of message
for 2A- than 2B-AR in most brain areas,
with the exception of the thalamus. Developing these probes for in situ
hybridization is an important step for further studies on the exact
role of the 2-AR subtypes in neurons that modulate
cardiovascular function.
Key Words: receptors, adrenergic, alpha • brain
|
Introduction |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
The
2-adrenergic receptors (2-ARs) are
believed to have an important role in the central regulation of
autonomic cardiovascular function.1 The
lower brain stem structures contain a high concentration of
2-ARs2 and are responsible for maintaining
vasomotor sympathetic tone.3 Moreover, the
2-ARs within the brain stem are the target of the
central hypotensive actions of clonidine.4
The 2-ARs are a heterogeneous group of
receptors that mediate their effects through the Gi class
of G proteins and bind to the naturally occurring ligands
epinephrine and norepinephrine. As in other G
protein–coupled receptors, 2-AR subtypes have been
identified that differ in their structure, pharmacological profile, and
tissue
distribution.5 6 7 8 9
Pharmacological and molecular
studies of 2-ARs have suggested at least three distinct
genes in both human and rat that code for three distinct subtypes,
designated 2A, 2B, and
2C.5 Recent studies show that all three
subtypes are found in brain and
kidney.6 7 10
Localization of 2-ARs in the rat brain has been
accomplished with radiolabeled ligands,11 and localization
of 2-AR transcripts has been done with RNAse protection
assays or Northern blots.7 10 However, these data
cannot
provide unequivocal information on the cellular distribution of the
various 2-AR subtypes because the
radioligands have broad specificities for the
2 class of receptors. Subtype-specific probes have
been used in protection analysis or Northern blots, but these
methods rely on the isolation of RNA from larger dissected tissue
sections. Recent reports have made progress in determining the
localization of these receptors in rat brain cells by using
immunohistochemistry or in situ
hybridization12 13 14 15 16 17 ;
however, there are inconsistencies among the several studies that used
in situ
hybridization.12 13 14 15 16 17
To address these problems, we developed a unique set of riboprobes, and
in this article we describe the localization of 2A- and
2B-ARs in the normotensive rat brain using in situ
hybridization with subtype-specific RNA probes.
|
Methods |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
Subtype-Specific Probes
We subcloned regions of the rat
2A- and
2B-AR genomic DNA and cDNA, respectively, into an SP6
promoter containing vector, psP65 (Promega), to allow the synthesis of
antisense RNA probes that are specific for transcripts from either the
2A- or 2B-AR genes. To detect the
2A mRNA, we subcloned a 600-bp
SstI/XbaI fragment that encompasses part of the
5' untranslated region of rat 2A transcript into psP65
at the Sst I/Xba I sites. A 269-bp Pst
I fragment of RNG2 cDNA was cloned into the
Pst I site of psP65 to create a probe specific for the
transcripts that encode the 2B-AR. RNG2
cDNA18 was a kind gift of Dr Kevin R. Lynch, University of
Virginia School of Medicine, Charlottesville, Va.
Tissue Preparation and In Situ Hybridization
Male Wistar rats
(250 to 300 g) under anesthesia
(sodium pentobarbital, 50 mg/kg IP) were perfused with cold (4°C)
phosphate-buffered saline for 3 to 5 minutes and decapitated. The
brain was rapidly removed and frozen in isopentane at -70°C.
Serial coronal cryostat sections (15 µm) of this material were
thaw-mounted onto silanized slides, rapidly dried, and stored at
-20°C until used (3 to 12 weeks). In situ hybridization
experiments were performed as previously described.19
Briefly, unfixed, adjacent tissue sections were thawed rapidly, air
dried, and incubated in 35 000 cpm/µL of one of the
35S-labeled RNA probes diluted in a hybridization solution
consisting of 50% deionized formamide, 0.3 mol/L NaCl, 20 mmol/L
Tris-HCl (pH 7.4), 5 mmol/L EDTA, 10 mmol/L
NaH2PO4·H2O (pH 8.0), 10%
dextran sulfate, 1x Denhardt's, and 0.5 mg/mL total yeast RNA.
Sections were incubated in humidified boxes at 52°C for 17 hours.
Sections were washed extensively in 0.75 mol/L NaCl, 0.075 mol/L sodium
citrate, and 10 mmol/L dithiothreitol for 30 minutes at 50°C and 0.30
mol/L NaCl, 0.030 mol/L sodium citrate, 50% formamide, and 0.1 mol/L
dithiothreitol for 20 minutes at 65°C before digestion with 0.02
mg/mL RNase A for 60 minutes at 37°C. After dehydration in a series
of ethanols from 30% to 100%, the slides were air-dried, dipped
in Kodak NTB2 autoradiography emulsion, and exposed
for 6-7 days in a light-free black plastic box at 4°C. Finally,
these slides were developed in Kodak D19 for 4 minutes at 14°C and
fixed in Kodak Rapid Fix A (solution A) for 3 minutes. Sections were
rinsed in distilled water, stained through the emulsion with 0.05%
thionin, and dehydrated in graded ethanols, and glass coverslips were
affixed with Cytoseal 60 mounting medium. All the sections were
examined under bright- and dark-field illumination with a
microscope. Photomicrographs were taken with Polaroid Type 55 or Kodak
Contrast Process Ortho 4x5 films. The identification and nomenclature
of rat brain structures were based on the atlas of Paxinos and
Watson.20
In addition to this microscopic analysis, we
also used a
computerized video densitometry system (Inquiry, Loats Associates) to
perform an overall analysis of the labeling obtained with these
two methods. In this case, one brain was sagittally sectioned, and
adjacent sections were processed with both sense and antisense probes
for both the 2A- and 2B-ARs. These
sections were then exposed on a single piece of Hyperfilm (Amersham)
for 5 days, after which the film was developed in D19 and digitized on
the Inquiry densitometry system. Since the overall labeling of the
2A-AR was much greater than for the
2B-AR, the background level of labeling of the
pseudocolor map was adjusted so that the range of densities for the two
probes was normalized. In this way, areas that differed from the global
mean could be visually revealed and used to confirm the differential
distribution and labeling of these two probes as well as to guide
further analysis.
Cell Lines
In situ hybridization of cultured cell lines was
performed after
cells were grown on chamber slides. These cells were not stained.
Permanently transfected CHO cells that express the rat
2A-AR (CHO-A), 2B-AR (CHO-B), and
2C-AR (CHO-C)7 were maintained in the alpha
modification of minimum essential medium without ribonucleosides and
deoxyribonucleosides supplemented with 10% fetal calf serum. For CHO-A
and CHO-C cells, we added 0.005 and 0.02 µmol/L methotrexate to the
media, respectively. Untransfected CHO cells (dhfr-) (CHO-d) were
grown in alpha minimum essential medium with ribonucleosides and
deoxyribonucleosides supplemented with 10% fetal calf serum. RINm5F
cells, a rat insulin–producing cell line that naturally expresses
the 2A-AR, were maintained in RPMI-1640 medium
supplemented with 10% fetal calf serum.21 All media were
from GIBCO/BRL.
RNase Protection Assay
RNA from Wistar rat brains was
isolated through a CsCl gradient
as described.22 RNase protection was performed as
described.23 Briefly, antisense probes were linearized
before RNA synthesis, and antisense RNA was synthesized in the presence
of [-32P]CTP (Amersham) with SP6 polymerase. RNA
duplexes were formed between the radiolabeled probe and RNA samples by
overnight hybridization at 45°C in 80% formamide, 0.4 mol/L NaCl, 1
mmol/L EDTA, and 40 mmol/L
piperazine-N,N'-bis(2-ethanesulfonic
acid) (PIPES) (pH 6.7). Single-stranded RNA was digested by a
mixture of RNase A and T1 at 37°C for 1 hour. Protected bands were
visualized on a denaturing 6 mol/L urea, 6% polyacrylamide
gel. Labeled pBR322 HinfI fragments were used as size
markers.
|
Results |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
In Situ Hybridization in Transfected CHO and RINm5F Cells
To verify the specificity and sensitivity of our probes, we performed in situ hybridization on permanently transfected CHO cells expressing
2A-, 2B-, and
2C-ARs and RINm5F cells. Fig 1
shows the
common structure of 2-AR and relative positions of rat
2A- and 2B-AR subtype probes.
|
The
2B antisense probe hybridizes strongly with the
transcripts in CHO-B cells (Fig 2A) but does not
hybridize to transcripts in the CHO-A (Fig 2C), CHO-C (Fig
2D), or
nontransfected CHO-d cells (Fig 2E), showing a high specificity
of this
probe for the rat 2B mRNA. The 2A
antisense probe strongly hybridizes to all the RINm5F cells (Fig
3A). Furthermore, the 2A probe did not
react positively against the CHO-B, CHO-C, or nontransfected CHO-d
cells (data not shown). Figs 2B and 3B also show
that 2B
and 2A sense probes, respectively, produce very little
background labeling.
|
|
RNase Protection
Dissection of brain into hypothalamus,
pons-medulla,
cerebellum, and cortex shows that the 2A-AR transcripts
are most concentrated in hypothalamus and pons-medulla, followed by
cortex, and are much lower in cerebellum (Fig 4). The
2B-AR probe shows a different distribution pattern, with
the strongest signal in hypothalamus, weaker bands in cerebellum and
cortex, and a faint but visible band in medulla.
|
In Situ Hybridization in Rat Brain
To begin the analysis of
2-AR subtypes in
brain, we studied the distribution of 2A- and
2B-AR mRNAs throughout the brain. Specificity of
hybridization was indicated by comparison between the low, generally
uniform levels of background labeling resulting from hybridization with
each labeled sense-strand RNA probe and the strikingly different
labeling pattern, the clustering of silver grains over neurons
characteristic of specific hybridization between RNA transcripts and
the antisense RNA probe. For example, Fig 5 shows a
typical comparison of the labeling patterns of sense and antisense
probes. Clusters of silver grains are present over neurons in the
cerebellum when either the 2A or 2B
antisense probe is used (Fig 5A and 5B,
respectively), whereas few
silver grains are apparent when either the 2A or
2B sense probe is used (Fig 5C and
5D, respectively).
Comparison of sense and antisense signals showed message for both the
2A- and 2B-ARs to be expressed throughout
the rat brain. The Table shows the relative distribution
of these receptor subtypes in various brain structures. Fig 6
represents a digitized scan of
autoradiographic images showing the localization of
2A and 2B mRNAs throughout the brain.
Overall, there appeared to be a greater expression of
2A- than 2B-AR in the brain, with the
exception of some thalamic structures.
|
|
|
Medulla
The most intense hybridization signal in the medulla
was seen with
the 2A probe in the lateral reticular nucleus,
hypoglossal nucleus, inferior olive, and ambiguous nucleus,
followed by the gigantocellular reticular nucleus and dorsal motor
nucleus of vagus (Table
). The spinal nucleus of the trigeminal
nucleus
of the solitary tract, and spinal vestibular nucleus were also labeled
by the 2A probe. As shown in Fig 7G,
7H, and 7I, the 2A probe showed
higher density of
2A message in the nucleus of XII than in the nucleus of
the solitary tract. The reverse distribution was found for the
2B message.
|
Although 2B transcripts
were never detected at the same
overall intensity as 2A transcripts in medulla,
relatively dense 2B labeling was seen in the lateral
reticular nucleus and nucleus of the solitary tract. The
gigantocellular reticular nucleus, dorsal motor nucleus of vagus,
hypoglossal nucleus, and inferior olive were labeled with
medium intensity, and the spinal nucleus of the trigeminal, ambiguous
nucleus, and spinal vestibular nucleus were weakly labeled by the
2B probe.
Cerebellum
Neurons of both the molecular and granule cell
layers of the
cerebellum (see Fig 5) were labeled with both the
2A and
2B probes, although the 2B signal was
less pronounced. Purkinje cells also showed more signal with the
2A probe, whereas 2B-specific labeling
was less pronounced (Table and Fig 7D, 7E, 7F).
Pons and Midbrain
Both 2A- and
2B-AR transcripts were
present at relatively high levels in the facial nucleus,
gigantocellular reticular nucleus, pontine nucleus, and motor
trigeminal nucleus (Table). In contrast, locus coeruleus showed
the
highest intensity signal with the 2A probe, and much
less 2B signal was detected (Fig 7D, 7E, 7F).
The
central gray was one of the few regions where the 2B-AR
appeared to be the dominant adrenoceptor. Dorsal and ventral cochlear
nuclei, parvicellular reticular nucleus, and dorsal and ventral
parabrachial nuclei showed similar, relatively intense signals of
2A- and 2B-ARs.
Forebrain
The structures of the hippocampus and cerebral
cortex showed
similar, high-intensity signals for both 2A- and
2B-ARs, although 2A was higher than
2B in the hippocampus and the superficial layers of the
neocortex (Fig 7A, 7B, 7C). In contrast, thalamus and
hypothalamus were
most strongly labeled by the 2B probe.
|
Discussion |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
We have mapped the localization of
2A- and
2B-AR mRNAs in brain by in situ hybridization and RNase
protection. These data suggest the presence of both of these messages
throughout the brain, with different intensity patterns. The regions
that appeared to have the most mRNA by protection assay (Fig 4)
did not
correlate with the regions that had the strongest signal, as judged by
intensity imaging (Fig 6) of the in situ data. However, the
protection
assay was performed per amount of total RNA, whereas the intensity
imaging was determined over an area of brain tissue. The in situ
hybridization signal was not affected by the amount of total RNA in a
particular structure, only the amount of the specific RNA targeted with
the probe. On the other hand, RNase protection measured the amount of a
particular 2-AR mRNA present in a mixture of RNAs.
In this case, the signal detected would be affected by the total amount
of RNA present.
Our results with the 2A probe largely agree with the
results of studies using immunohistochemical
methods12 13
as well as an in situ study by Nicholas et al.15 However,
the current study has several differences compared with other in situ
studies.16 17 For example, these other studies did
not
find 2A-AR expression in thalamus or the trigeminal
nucleus, whereas we found 2A mRNA in both of these
regions and in especially high levels in the trigeminal nucleus. In
addition, we found 2A-AR mRNA in both the granule cell
and molecular layers of the cerebellum, in contrast to Scheinin et
al,17 who reported 2A mRNA only in the
granule cell layer.
Unlike Nicholas et al,15 we detected 2B
mRNA throughout the brain, whereas their report finds the
2B-AR only in the thalamic structures. This is in
contrast to an earlier article by this same group that reported
2B expression throughout the brain.14
Most of the other in situ studies14 15 16 used end-labeled oligonucleotide probes, whereas we used single-stranded RNA probes that are synthesized in the presence of a radiolabeled ribonucleotide, producing a probe that is labeled throughout the synthesized RNA. Because of these differences in probes, the investigators with oligonucleotide probes used 4 to 6 weeks of exposure time. Similarly, another report17 used full-length cDNA to produce riboprobes; however, these investigators apparently used much fewer counts per microliter in their probe hybridizations and 8 weeks of exposure time. In contrast, we used only 6-7 days of exposure time. This suggests that our probes are much more sensitive than the oligonucleotide probes, and by altering probes and counts, we can detect much lower levels of mRNA with riboprobes than with oligonucleotide probes.
One could argue that cross-hybridization of our probes could
account for our results. However, our probes have been extensively
tested against cell lines that express only one 2-AR
subtype, with no evidence for cross-reactivity. In addition, there
are structures of the brain where the relative intensities of
2B and 2A differ; for example, in the
medulla, the 2B message is more abundant in the nucleus
of the solitary tract than the nucleus of XII, and the
2A message is more abundant in the nucleus of XII than
the nucleus of the solitary tract. If the 2B
cross-hybridizes to 2A mRNA, then one would expect
to find 2B signal greatest in the regions where
2A has the greatest expression. This indicates that
choosing RNA probes gives a higher sensitivity and specificity for
visualization of various brain structures. It also suggests that
cross-hybridization should be tested in known cell structures or
cell lines that express a specific mRNA.
Our results have many implications for understanding the role of
2-AR in controlling cardiovascular
regulation. We have found 2A- and 2B-AR
mRNA in neurons of the central pathways involved in baroreflex, ie,
within regions such as the nucleus of the solitary tract, the dorsal
motor nucleus of the vagus, the ambiguous nucleus, the
inferior olive, and the reticular nucleus. Both
2A- and 2B-AR mRNAs are also detected in
other areas involved with blood pressure regulation and the control of
sympathetic outflow, such as the locus coeruleus or hypothalamus,
although 2A predominates in the locus coeruleus. Our
studies cannot determine whether both receptors are present in the
same neurons or whether both receptors contribute to the control of
arterial and pulse pressures. Analysis of subtype
expression patterns in hypertensive versus normotensive animal models
may provide insights into which subtype controls blood pressure.
Previous studies have described differences in central
2-AR levels in normotensive and hypertensive
animals.24 25 26 These studies have shown
specific
alterations in 2-AR in the medulla24 and
alterations of 2-AR mRNA in the
pons-medulla26 regions of spontaneously hypertensive
versus Wistar-Kyoto rats. However, these studies did not precisely
localize these changes. It is possible that in situ analysis
will show whether these differences in expression occur in a region of
the pons-medulla involved in blood pressure control. However, it is
likely that more direct methods that can block or stimulate only one
2-AR subtype may be necessary to clarify the role of
each 2-AR subtype in cardiovascular
function. For example, antisense therapies or knockout animal models
may be used to block specific subtype expression, or specific drugs can
be used to inhibit or stimulate a single 2-AR
subtype.
In terms of applying any findings in animal models to treatment
strategies for human hypertension, the human brain has many more levels
of complexity. In addition, although there are three
2-AR subtypes in human and rodent species, previous work
has shown that differences in the pharmacology of analogous
2A-ARs in rodents and humans arise from a few specific
nucleotide changes that specify changes in key amino acid
residues and result in distinct ligand binding properties of highly
related proteins.27 Likewise, genetic differences in
regulatory regions of human and rodent 2-AR genes could
contribute to differences in tissue-specific expression patterns
between species.
In conclusion, using RNA antisense probes, we have found a
significantly different distribution of mRNAs for 2-AR
subtypes than other researchers using DNA probes. In addition to the
increased sensitivity, we have found the RNA probes to be less
time-consuming to use, with no evidence for
cross-hybridization. Developing these probes for in situ
hybridization is an important step for further studies on the exact
role of the 2-AR subtypes in
cardiovascular function modulated by neurons expressing
these receptors.
|
Acknowledgments |
|---|
This study was supported by National Institutes of Health grants P01 AG00001, P01 NS31649, HL-48181, and HL-46693. Agostinho Tavares was supported in part by Brazilian grants 201579/90.1 (CNPq) and 93/4414-9 (FAPESP). We acknowledge the excellent technical assistance of Andrew Doolittle, Claudia Fitzgerald, and Ramy Rizkalla in the Department of Anatomy and Neurobiology.
Received September 12, 1995; first decision October 23, 1995; accepted November 6, 1995.
|
References |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
1. Hausler G. Cardiovascular regulation by central adrenergic mechanism and characterization by hypertensive drugs. Circ Res. 1975;36/37(suppl I):I-232-I-233.
2. Unnerstall JR, Kopajtic TA, Kuhar MJ. Distribution of alpha2 agonist binding sites in the rat and human central nervous system: analysis of some functional, anatomic correlates of the pharmacologic effects of clonidine and related adrenergic agents. Brain Res. 1984;319:69-101. [Medline] [Order article via Infotrieve]
3. Reis JD, Golanov EV, Ruggiero DA, Sun MK. Sympatho-excitatory neurons of the rostral ventrolateral medulla are oxygen sensors and essential elements in the tonic and reflex control of the systemic and cerebral circulations. J Hypertens. 1994;12:S159-S180.
4. Punnen S, Urbanski R, Krieger AJ, Sapru HN. Ventrolateral medullary pressor area: site of hypotensive action of clonidine. Brain Res. 1987;422:336-346. [Medline] [Order article via Infotrieve]
5.
Bylund DB. Subtypes of 1 and
2-adrenergic receptors. FASEB J. 1992;6:832-839. [Abstract]
6.
Lorenz W, Lomasney JW, Collins S, Regan JW, Caron MG,
Lefkowitz RJ. Expression of three 2-adrenergic
receptor subtypes in rat tissues: implications for receptor
classification. Mol Pharmacol. 1990;38:599-603. [Abstract]
7.
Handy DE, Flordellis CS, Bogdanova NN, Bresnahan MR,
Gavras H. Diverse tissue expression of
2-adrenergic receptor genes.
Hypertension. 1993;21:861-865.
8.
Coupry I, Duzic E, Lanier SM. Factors
determining the specificity of signal transduction by guanine
nucleotide-binding protein-coupled receptors, II:
preferential coupling of the 2C-adrenergic receptor to
the guanine nucleotide binding protein,
Go. J Biol Chem. 1992;267:9852-9857.
9.
Flordellis CS, Berguerand M, Gouache P, Barbu V,
Gavras H, Handy DE, Bereziat G, Masliah J.
2-adrenergic receptor subtypes expressed in Chinese
hamster ovary cells activate differentially
mitogen-activated protein kinase by a p21ras
independent pathway. J Biol Chem. 1995;270:3491-3494.
10. Zeng D, Lynch KR. Distribution of alpha-2 adrenergic receptor mRNAs in the rat CNS. Mol Brain Res. 1991;10:219-225. [Medline] [Order article via Infotrieve]
11.
Boyajian CL, Loughlin SE, Leslie FM. Anatomical
evidence for alpha-2 adrenoceptor heterogeneity:
differential autoradiographic distribution of
[3H]rauwolcine and [3H]idaxozan in rat brain. J
Pharmacol Exp Ther. 1987;241:1079-1091.
12. Rosin DL, Zeng D, Stornetta RL, Norton FR, Riley T, Okusa MD, Guyenet PG, Lynch KR. Immunohistochemical localization of alpha2A-adrenergic receptors in catecholaminergic and other brainstem neurons in the rat. Neuroscience. 1993;56:139-155. [Medline] [Order article via Infotrieve]
13. Aoki C, Go CG. Perikaryal and synaptic localization of alpha 2A-adrenergic receptor-like immunoactivity. Brain Res. 1994;650:181-204. [Medline] [Order article via Infotrieve]
14. Nicholas AP, Pieribone VA, Elde R, Hokfelt T. Initial observations on the localization of mRNA for alpha and beta adrenergic receptors in brain and peripheral tissues of rat using in situ hybridization. Mol Cell Neurosci. 1991;2:344-350.
15. Nicholas AP, Pieribone V, Hokfelt T. Distributions of mRNAs for alpha-2 adrenergic receptor subtypes in rat brain: an in situ hybridization study. J Comp Neurol. 1993;328:575-594. [Medline] [Order article via Infotrieve]
16. McCune SK, Voigt MM, Hill JM. Expression of multiple alpha-adrenergic receptor subtype messenger RNAs in the adult rat brain. Neuroscience. 1993;57:143-151. [Medline] [Order article via Infotrieve]
17.
Scheinin M, Lomasney JW, Hayden-Hixson DM, Schambra UB,
Caron MG, Lefkowitz RJ, Fremeau RT Jr. Distribution of
2-adrenergic receptor subtype gene expression in rat
brain. Mol Brain Res. 1994;21:133-149. [Medline]
[Order article via Infotrieve]
18.
Zeng D, Harrison JK, D'Angelo DD, Barber CM, Tucker
AL, Lu Z, Lynch KR. Molecular characterization of a rat
alpha2B-adrenergic receptor. Proc Natl Acad Sci
U S A. 1990;87:3102-3106.
19. Sassoon D, Lyons G, Wright WE, Lin V, Lassar A, Weintraub H, Buckingham M. Expression of two myogenic regulatory factors myogenin and myoD1 during mouse embryogenesis. Nature. 1989;341:303-307. [Medline] [Order article via Infotrieve]
20. Paxinos G, Watson C. The Rat Brain in Stereotaxic Coordinates. New York, NY: Academic Press; 1982.
21. Praz GA, Halban PA, Wollheim CB, Blondel B, Strauss AJ, Renold AE. Regulation of immunoreactive-insulin release from a rat cell line (RINm5F). Biochem J. 1983;210:345-352. [Medline] [Order article via Infotrieve]
22.
Flordellis C, Handy DE, Bresnahan MR, Zannis VI, Gavras
H. Cloning and expression of a rat brain alpha2B-adrenergic
receptor. Proc Natl Acad Sci U S A. 1991;88:1019-1023.
23. Handy DE, McCluskey J, Lew AM, Coligan JE, Margulies DH. Signals controlling alternative splicing of major histocompatibility complex H-2 class I pre-mRNA. Immunogenetics. 1988;28:81-90. [Medline] [Order article via Infotrieve]
24.
Yamada S, Ashizawa N, Nakayama K, Tomita T, Hayashi
E. Decreased density of 2-adrenoceptors in
medulla oblongata of spontaneously hypertensive rats.
J Cardiovasc Pharmacol. 1989;13:440-446. [Medline]
[Order article via Infotrieve]
25. Olmos G, Miralles A, Basturent G, Garcia-Sevilla JA. Decreased density and sensitivity of alpha-2-adrenoceptors in the brain of spontaneously hypertensive rats. Eur J Pharmacol. 1991;205:93-96. [Medline] [Order article via Infotrieve]
26. Castellano M, Handy DE, Flordellis C, Beschi M, Gavras H. Gene expression of catecholaminergic receptors in the central nervous system of hypertensive rats. J Hypertens. 1991;9:S54-S55.
27.
Link R, Daunt D, Barsh G, Chruscinski A, Kobilka
B. Cloning of two mouse genes encoding
2-adrenergic receptor subtypes and identification of a
single amino acid in the mouse 2-C10 homolog responsible
for an interspecies variation in antagonist
binding. Mol Pharmacol. 1992;42:16-27.[Abstract]
This article has been cited by other articles:
 |
|
 |
|
  Z. Xie, S. V. Westmoreland, and G. M. Miller Modulation of Monoamine Transporters by Common Biogenic Amines via Trace Amine-Associated Receptor 1 and Monoamine Autoreceptors in Human Embryonic Kidney 293 Cells and Brain Synaptosomes J. Pharmacol. Exp. Ther., May 1, 2008; 325(2): 629 - 640. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D.-P. Li, L. M. Atnip, S.-R. Chen, and H.-L. Pan Regulation of Synaptic Inputs to Paraventricular-Spinal Output Neurons by {alpha}2 Adrenergic Receptors J Neurophysiol, January 1, 2005; 93(1): 393 - 402. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. J. Pauwels, I. Rauly, and T. Wurch Dissimilar Pharmacological Responses by a New Series of Imidazoline Derivatives at Precoupled and Ligand-Activated {alpha}2A-Adrenoceptor States: Evidence for Effector Pathway-Dependent Differential Antagonism J. Pharmacol. Exp. Ther., June 1, 2003; 305(3): 1015 - 1023. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. F. Davies, F. Haimor, G. Lighthall, and J. D. Clark Dexmedetomidine Fails to Cause Hyperalgesia After Cessation of Chronic Administration Anesth. Analg., January 1, 2003; 96(1): 195 - 200. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Reja, A. K. Goodchild, and P. M. Pilowsky Catecholamine-Related Gene Expression Correlates With Blood Pressures in SHR Hypertension, September 1, 2002; 40(3): 342 - 347. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Plut, C. Ribiere, Y. Giudicelli, and J.-P. Dausse Gender Differences in Hypothalamic Tyrosine Hydroxylase and alpha 2-Adrenoceptor Subtype Gene Expression in Cafeteria Diet-Induced Hypertension and Consequences of Neonatal Androgenization J. Pharmacol. Exp. Ther., August 1, 2002; 302(2): 525 - 531. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. J. A. Janssen and J. F. M. Smits Autonomic control of blood pressure in mice: basic physiology and effects of genetic modification Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2002; 282(6): R1545 - R1564. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Yamazato, A. Sakima, J. Nakazato, S. Sesoko, H. Muratani, and K. Fukiyama Hypotensive and sedative effects of clonidine injected into the rostral ventrolateral medulla of conscious rats Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2001; 281(6): R1868 - R1876. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Kintsurashvili, I. Gavras, C. Johns, and H. Gavras Effects of Antisense Oligodeoxynucleotide Targeting of the {alpha}2B-Adrenergic Receptor Messenger RNA in the Central Nervous System Hypertension, November 1, 2001; 38(5): 1075 - 1080. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Snapir, P. Heinonen, T.-P. Tuomainen, P. Alhopuro, M. K. Karvonen, T. A. Lakka, K. Nyyssonen, R. Salonen, J. Kauhanen, V.-P. Valkonen, et al. An insertion/deletion polymorphism in the {alpha}2b-adrenergic receptor gene is a novel genetic risk factor for acute coronary events J. Am. Coll. Cardiol., May 1, 2001; 37(6): 1516 - 1522. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. P. Makaritsis, C. Johns, I. Gavras, and H. Gavras Role of {alpha}2-Adrenergic Receptor Subtypes in the Acute Hypertensive Response to Hypertonic Saline Infusion in Anephric Mice Hypertension, February 1, 2000; 35(2): 609 - 613. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Zhang, V. Klimek, J. T. Farley, M.-Y. Zhu, and G. A. Ordway alpha 2C Adrenoceptors Inhibit Adenylyl Cyclase in Mouse Striatum: Potential Activation by Dopamine J. Pharmacol. Exp. Ther., June 1, 1999; 289(3): 1286 - 1292. [Abstract] [Full Text]
|
|
|
|
|
|
K. P. Makaritsis, D. E. Handy, C. Johns, B. Kobilka, I. Gavras, and H. Gavras Role of the {alpha}2B-Adrenergic Receptor in the Development of Salt-Induced Hypertension Hypertension, January 1, 1999; 33(1): 14 - 17. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. E. Handy, C. Johns, M. R. Bresnahan, A. Tavares, M. Bursztyn, and H. Gavras Expression of {alpha}2-Adrenergic Receptors in Normal and Atherosclerotic Rabbit Aorta Hypertension, August 1, 1998; 32(2): 311 - 317. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. M. Small, K. M. Brown, S. L. Forbes, and S. B. Liggett Polymorphic Deletion of Three Intracellular Acidic Residues of the alpha 2B-Adrenergic Receptor Decreases G Protein-coupled Receptor Kinase-mediated Phosphorylation and Desensitization J. Biol. Chem., February 9, 2001; 276(7): 4917 - 4922. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||