| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Anesthesiology, Baylor College of Medicine, Houston, TX, USA
* To whom correspondence should be addressed. E-mail: marrelli{at}bcm.tmc.edu.
The present study evaluated the role of endothelial intermediate conductance calcium-sensitive K+ channels (IKCa) in the mechanism of endothelium-derived hyperpolarizing factor (EDHF)-mediated dilations in pressurized cerebral arteries. Male rat middle cerebral arteries (MCA) were mounted in an isolated vessel chamber, pressurized (85 mmHg), and luminally perfused (100 µl/min). Artery diameter was measured simultaneously with either endothelial [Ca2+]i (fura 2) or changes in endothelial membrane potential (di-8-ANEPPS). NOS and cyclooxygenase inhibitors were present throughout. Luminal application of UTP produced EDHF-mediated dilations that correlated with significant endothelial hyperpolarization. The dilation and endothelial hyperpolarization were virtually abolished by inhibitors of IKCa channels but not by selective inhibitors of small or large conductance KCa channels (apamin and iberiotoxin, respectively). Additionally, direct stimulation of endothelial IK channels with 1-EBIO produced endothelial hyperpolarization and vasodilatation that was blocked by inhibitors of IKCa channels. 1-EBIO hyperpolarized the endothelium but did not affect endothelial [Ca2+]i. We conclude that the mechanism of EDHF-mediated dilations in cerebral arteries requires stimulation of endothelial IKCa channels to promote endothelial hyperpolarization and subsequent vasodilatation.
This article has been cited by other articles:
|
|
 |
|
  P. D. Smith, S. E. Brett, K. D. Luykenaar, S. L. Sandow, S. P. Marrelli, E. J. Vigmond, and D. G. Welsh KIR channels function as electrical amplifiers in rat vascular smooth muscle J. Physiol., February 15, 2008; 586(4): 1147 - 1160. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. A. Dabisch, J. T. Liles, S. R. Baber, N. H. Golwala, S. N. Murthy, and P. J. Kadowitz Analysis of L-NAME-dependent and -resistant responses to acetylcholine in the rat Am J Physiol Heart Circ Physiol, February 1, 2008; 294(2): H688 - H698. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. S. Silva, A. Kapela, and N. M. Tsoukias A mathematical model of plasma membrane electrophysiology and calcium dynamics in vascular endothelial cells Am J Physiol Cell Physiol, July 1, 2007; 293(1): C277 - C293. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. X. Zhang, K. M. Gauthier, Y. Chawengsub, and W. B. Campbell ACh-induced relaxations of rabbit small mesenteric arteries: role of arachidonic acid metabolites and K+ Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H152 - H159. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. P. Marrelli, R. G. O'Neil, R. C. Brown, and R. M. Bryan Jr. PLA2 and TRPV4 channels regulate endothelial calcium in cerebral arteries Am J Physiol Heart Circ Physiol, March 1, 2007; 292(3): H1390 - H1397. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. M. Sokoya, A. R. Burns, C. T. Setiawan, H. A. Coleman, H. C. Parkington, and M. Tare Evidence for the involvement of myoendothelial gap junctions in EDHF-mediated relaxation in the rat middle cerebral artery Am J Physiol Heart Circ Physiol, July 1, 2006; 291(1): H385 - H393. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Ledoux, M. E. Werner, J. E. Brayden, and M. T. Nelson Calcium-Activated Potassium Channels and the Regulation of Vascular Tone Physiology, February 1, 2006; 21(1): 69 - 78. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Andresen, N. I. Shafi, and R. M. Bryan Jr. Endothelial influences on cerebrovascular tone J Appl Physiol, January 1, 2006; 100(1): 318 - 327. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. You, E. M. Golding, and R. M. Bryan Jr. Arachidonic acid metabolites, hydrogen peroxide, and EDHF in cerebral arteries Am J Physiol Heart Circ Physiol, September 1, 2005; 289(3): H1077 - H1083. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. J. Alvarez, A. C. Zamudio, and O. A. Candia Cl- secretory effects of EBIO in the rabbit conjunctival epithelium Am J Physiol Cell Physiol, July 1, 2005; 289(1): C138 - C147. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. M. Faraci, C. Lynch, and K. G. Lamping Responses of cerebral arterioles to ADP: eNOS-dependent and eNOS-independent mechanisms Am J Physiol Heart Circ Physiol, December 1, 2004; 287(6): H2871 - H2876. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. van Bavel Shear stress and intermediate-conductance calcium-activated potassium channels Cardiovasc Res, December 1, 2003; 60(3): 457 - 459. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
