This Article Full Text 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 Sirous, Z. N. Articles by Khalil, R. A. Search for Related Content PubMed PubMed Citation Articles by Sirous, Z. N. Articles by Khalil, R. A. Related Collections Calcium cycling/excitation-contraction coupling Cell signalling/signal transduction CV surgery: valvular disease Other Vascular biology

(Hypertension. 2001;37:497.)
© 2001 American Heart Association, Inc.

Scientific Contributions

Endothelin-1 Enhances Eicosanoids-Induced Coronary Smooth Muscle Contraction by Activating Specific Protein Kinase C Isoforms

Zohreh N. Sirous; John B. Fleming; Raouf A. Khalil

From the Department of Physiology and Biophysics and the Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson.

Correspondence to Raouf A. Khalil, MD, PhD, Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216. E-mail: rkhalil{at}physiology.umsmed.edu

Endothelin-1 (ET-1), a potent vasoconstrictor, has been implicated in the pathogenesis of coronary vasospasm by enhancing coronary vasoconstriction to vasoactive eicosanoids; however, the cellular mechanisms involved are unclear. We investigated whether physiological concentrations of ET-1 enhance coronary smooth muscle contraction to vasoactive eicosanoids by activating specific protein kinase C (PKC) isoforms. Cell contraction was measured in single smooth muscle cells isolated from porcine coronary arteries, intracellular free Ca²⁺ ([Ca²⁺]_i) was measured in fura-2–loaded cells, and the cytosolic and particulate fractions were examined for PKC activity and reactivity with isoform-specific anti-PKC antibodies using Western blots. In Hanks’ solution (1 mmol/L Ca²⁺), ET-1 (10 pmol/L) did not increase basal [Ca²⁺]_i (81±2 nmol/L), but it did cause cell contraction (9%) that was inhibited by GF109203X (10^–6 mol/L), an inhibitor of Ca²⁺-dependent and Ca²⁺-indpendent PKC isoforms. The vasoactive eicosanoid prostaglandin F₂ (PGF₂, 10^–7 mol/L) caused increases in cell contraction (11%) and [Ca²⁺]_i (108±7 nmol/L) that were inhibited by the Ca²⁺ channel blocker diltiazem (10^–6 mol/L). Pretreatment with ET-1 (10 pmol/L) for 10 minutes enhanced cell contraction to PGF₂ (35%) with no additional increase in [Ca²⁺]_i (112±8 nmol/L). Direct activation of PKC by phorbol 12,13-dibutyrate (PDBu, 10^–7 mol/L) caused cell contraction (10%) and enhanced PGF₂ contraction (33%) with no additional increase in [Ca²⁺]_i (115±7 nmol/L). The ET-1–induced enhancement of PGF₂ contraction was inhibited by Gö6976 (10^–6 mol/L), an inhibitor of Ca²⁺-dependent PKC isoforms. Both ET-1 and PDBu caused an increase in PKC activity in the particulate fraction and a decrease in the cytosolic fraction and increased the particulate/cytosolic PKC activity ratio. Western blots revealed the Ca²⁺-dependent -PKC and the Ca²⁺-independent -, -, and -PKC isoforms. In resting tissues, - and -PKC were mainly cytosolic, -PKC was mainly in the particulate fraction, and -PKC was equally distributed in the cytosolic and particulate fraction. ET-1 (10 pmol/L) alone or PDBu (10^–7 mol/L) alone caused translocation of -PKC from the cytosolic to the particulate fraction, localized -PKC more in the particulate fraction, but did not change the distribution of -PKC. PGF₂ (10^–7 mol/L) alone did not change PKC activity. In tissues pretreated with ET-1 or PDBu, PGF₂ caused additional increases in -PKC activity. Thus, the enhancement of PGF₂-induced coronary smooth muscle contraction by physiological concentrations of ET-1 involves activation and translocation of -PKC in addition to - and -PKC isoforms, and this may represent one possible cellular mechanism by which ET-1 could enhance coronary vasoconstriction to vasoactive eicosanoids in coronary vasospasm.

Key Words: endothelin • prostaglandin • calcium • muscle, smooth, vascular • myocardial contraction

This article has been cited by other articles:

				D. S. Wijesinghe, P. Subramanian, N. F. Lamour, L. B. Gentile, M. H. Granado, A. Bielawska, Z. Szulc, A. Gomez-Munoz, and C. E. Chalfant Chain length specificity for activation of cPLA2{alpha} by C1P: use of the dodecane delivery system to determine lipid-specific effects J. Lipid Res., October 1, 2009; 50(10): 1986 - 1995. [Abstract] [Full Text] [PDF]

				C. P. Nelson, J. M. Willets, N. W. Davies, R. A. J. Challiss, and N. B. Standen Visualizing the temporal effects of vasoconstrictors on PKC translocation and Ca2+ signaling in single resistance arterial smooth muscle cells Am J Physiol Cell Physiol, December 1, 2008; 295(6): C1590 - C1601. [Abstract] [Full Text] [PDF]

				K. J. Allahdadi, L. C. Duling, B. R. Walker, and N. L. Kanagy Eucapnic intermittent hypoxia augments endothelin-1 vasoconstriction in rats: role of PKC{delta} Am J Physiol Heart Circ Physiol, February 1, 2008; 294(2): H920 - H927. [Abstract] [Full Text] [PDF]

				H. Zhang and L. Zhang Role of Protein Kinase C Isozymes in the Regulation of alpha1-Adrenergic Receptor-Mediated Contractions in Ovine Uterine Arteries Biol Reprod, January 1, 2008; 78(1): 35 - 42. [Abstract] [Full Text] [PDF]

				K. J. Allahdadi, B. R. Walker, and N. L. Kanagy ROK contribution to endothelin-mediated contraction in aorta and mesenteric arteries following intermittent hypoxia/hypercapnia in rats Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H2911 - H2918. [Abstract] [Full Text] [PDF]

				D. H. Korzick, J. M. Muller-Delp, P. Dougherty, C. L. Heaps, D. K. Bowles, and K. K. Krick Exaggerated coronary vasoreactivity to endothelin-1 in aged rats: Role of protein kinase C Cardiovasc Res, May 1, 2005; 66(2): 384 - 392. [Abstract] [Full Text] [PDF]

				B. Kim, J. Kim, Y. M. Bae, S. I. Cho, S. C. Kwon, J. Y Jung, J.-C. Park, and H. Y. Ahn p38 Mitogen-Activated Protein Kinase Contributes to the Diminished Aortic Contraction by Endothelin-1 in DOCA-Salt Hypertensive Rats Hypertension, May 1, 2004; 43(5): 1086 - 1091. [Abstract] [Full Text] [PDF]

				C. Lan, D. Das, A. Wloskowicz, and B. Vollrath Endothelin-1 modulates hemoglobin-mediated signaling in cerebrovascular smooth muscle via RhoA/Rho kinase and protein kinase C Am J Physiol Heart Circ Physiol, January 1, 2004; 286(1): H165 - H173. [Abstract] [Full Text] [PDF]

				L. Smith, J. A. Payne, M. H. Sedeek, J. P. Granger, and R. A. Khalil Endothelin-Induced Increases in Ca2+ Entry Mechanisms of Vascular Contraction Are Enhanced During High-Salt Diet Hypertension, March 1, 2003; 41(3): 787 - 793. [Abstract] [Full Text] [PDF]

				R. Maas, E. Schwedhelm, J. Albsmeier, and R. H Boger The pathophysiology of erectile dysfunction related to endothelial dysfunction and mediators of vascular function Vascular Medicine, August 1, 2002; 7(3): 213 - 225. [Abstract] [PDF]

				S. Chrissobolis and C. G. Sobey Inhibitory Effects of Protein Kinase C on Inwardly Rectifying K+- and ATP-Sensitive K+ Channel-Mediated Responses of the Basilar Artery Stroke, June 1, 2002; 33(6): 1692 - 1697. [Abstract] [Full Text] [PDF]

				A. E. Cain, D. M. Tanner, and R. A. Khalil Endothelin-1-Induced Enhancement of Coronary Smooth Muscle Contraction via MAPK-Dependent and MAPK-Independent [Ca2+]i Sensitization Pathways Hypertension, February 1, 2002; 39(2): 543 - 549. [Abstract] [Full Text] [PDF]