|
|
||||||||
Vascular Physiology Group, Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131-5218
Blunted agonist-induced vasoconstriction after chronic hypoxia is associated with endothelium-dependent vascular smooth muscle (VSM) cell hyperpolarization and decreased vessel-wall Ca2+ concentration ([Ca2+]). We hypothesized that myogenic vasoconstriction and pressure-induced Ca2+ influx would also be attenuated in vessels from chronically hypoxic (CH) rats. Mesenteric resistance arteries isolated from CH [barometric pressure (BP), 380 Torr for 48 h] or normoxic control (BP, 630 Torr) rats were cannulated and pressurized. VSM cell resting membrane potential was recorded at intraluminal pressures of 40-120 Torr under normoxic conditions. VSM cells in vessels from CH rats were hyperpolarized compared with control rats at all pressures. Inner diameter was maintained for vessels from control rats, whereas vessels from CH rats developed less tone as pressure was increased. Pressure-induced increases in vessel-wall [Ca2+] were also attenuated for arteries from CH rats. Endothelium removal restored myogenic constriction to vessels from CH rats and normalized VSM cell resting membrane potential and pressure-induced Ca2+ responses to control levels. Myogenic constriction and pressure-induced vessel-wall [Ca2+] increases remained blunted in the presence of nitric oxide (NO) synthase inhibition for arteries from CH rats. We conclude that blunted myogenic reactivity after chronic hypoxia results from a non-NO, endothelium-dependent VSM cell hyperpolarizing influence.
rat; calcium imaging; membrane potential; mesenteric circulation
This article has been cited by other articles:
![]() |
B. R. S. Broughton, B. R. Walker, and T. C. Resta Chronic hypoxia induces Rho kinase-dependent myogenic tone in small pulmonary arteries Am J Physiol Lung Cell Mol Physiol, April 1, 2008; 294(4): L797 - L806. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. B. Manukhina, H. F. Downey, and R. T. Mallet Role of nitric oxide in cardiovascular adaptation to intermittent hypoxia. Experimental Biology and Medicine, April 1, 2006; 231(4): 343 - 365. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. A. Phillips, E. B. Olson, J. H. Lombard, and B. J. Morgan Chronic intermittent hypoxia alters NE reactivity and mechanics of skeletal muscle resistance arteries J Appl Physiol, April 1, 2006; 100(4): 1117 - 1123. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. J. Campen, N. S. Babu, G. A. Helms, S. Pett, J. Wernly, R. Mehran, and J. D. McDonald Nonparticulate Components of Diesel Exhaust Promote Constriction in Coronary Arteries from ApoE-/- Mice Toxicol. Sci., November 1, 2005; 88(1): 95 - 102. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. E. Foster, D. C. McKenzie, W. K. Milsom, and A. W. Sheel Effects of two protocols of intermittent hypoxia on human ventilatory, cardiovascular and cerebral responses to hypoxia J. Physiol., September 1, 2005; 567(2): 689 - 699. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. S. Naik, S. Earley, T. C. Resta, and B. R. Walker Pressure-induced smooth muscle cell depolarization in pulmonary arteries from control and chronically hypoxic rats does not cause myogenic vasoconstriction J Appl Physiol, March 1, 2005; 98(3): 1119 - 1124. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. S. Naik and B. R. Walker Heme oxygenase-mediated vasodilation involves vascular smooth muscle cell hyperpolarization Am J Physiol Heart Circ Physiol, June 5, 2003; 285(1): H220 - H228. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Earley and B. R. Walker Increased nitric oxide production following chronic hypoxia contributes to attenuated systemic vasoconstriction Am J Physiol Heart Circ Physiol, May 1, 2003; 284(5): H1655 - H1661. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. S. Naik, T. L. O'Donaughy, and B. R. Walker Endogenous carbon monoxide is an endothelial-derived vasodilator factor in the mesenteric circulation Am J Physiol Heart Circ Physiol, March 1, 2003; 284(3): H838 - H845. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Osol and J. Brayden Prologue: vascular myogenic mechanisms Am J Physiol Heart Circ Physiol, December 1, 2002; 283(6): H2157 - H2159. [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |