| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Biomedical Sciences, College of Veterinary Medicine, and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211
We examined the contribution of K+-channel activity on basal tone and adenosine-mediated relaxation of coronary arterioles isolated from sexually mature male and female miniature swine. Arterioles (~100-200 µm ID) isolated from the apical region of the heart were cannulated and studied using videodimensional analysis under constant intraluminal pressure. Coronary arterioles from male and female pigs demonstrated similar levels of basal tone and reductions in basal diameter in response to the K+-channel blockers 4-aminopyridine (4-AP; 1 mM), tetraethylammonium (1 mM), and glibenclamide (Glib; 10 µM), with 4-AP producing significantly greater constriction than tetraethylammonium or Glib. After endothelin-induced preconstriction, relaxation responses to adenosine were not significantly different between coronary arterioles of male and female pigs. Inhibition of 4-AP-sensitive channels significantly impaired adenosine-mediated relaxation in arterioles from male but not female pigs. However, inhibition of K+ channels with iberiotoxin (100 nM) or Glib had no effect on adenosine-induced relaxation in either sex. Results obtained in the presence of nitric oxide synthase inhibition suggest a potential interaction of 4-AP-sensitive channels and nitric oxide at low adenosine concentrations. In conclusion, our data indicate that 4-AP-sensitive channels 1) contribute significantly to basal tone in coronary arterioles of both male and female pigs, 2) contribute to adenosine-mediated relaxation in male but not female pigs, and 3) can contribute to adenosine-induced relaxation independent of nitric oxide production in male pigs. These data are consistent with a significant role for voltage-dependent K+ channels in adenosine-mediated relaxation of coronary arterioles from males.
potassium channel; smooth muscle; endothelium; nitric oxide synthase; endothelin
This article has been cited by other articles:
|
|
 |
|
  G. M. Dick, I. N. Bratz, L. Borbouse, G. A. Payne, U. D. Dincer, J. D. Knudson, P. A. Rogers, and J. D. Tune Voltage-dependent K+ channels regulate the duration of reactive hyperemia in the canine coronary circulation Am J Physiol Heart Circ Physiol, May 1, 2008; 294(5): H2371 - H2381. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Yang, A. W. Jones, T. R. Thomas, and L. J. Rubin Influence of sex, high-fat diet, and exercise training on potassium currents of swine coronary smooth muscle Am J Physiol Heart Circ Physiol, September 1, 2007; 293(3): H1553 - H1563. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Qamirani, H. M. Razavi, X. Wu, M. J. Davis, L. Kuo, and T. W. Hein Sodium azide dilates coronary arterioles via activation of inward rectifier K+ channels and Na+-K+-ATPase Am J Physiol Heart Circ Physiol, April 1, 2006; 290(4): H1617 - H1623. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. M. Lynch, C. Austin, A. M. Heagerty, and A. S. Izzard Adenosine and hypoxic dilation of rat coronary small arteries: roles of the ATP-sensitive potassium channel, endothelium, and nitric oxide Am J Physiol Heart Circ Physiol, March 1, 2006; 290(3): H1145 - H1150. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. L. Heaps, M. L. Mattox, K. A. Kelly, C. J. Meininger, and J. L. Parker Exercise training increases basal tone in arterioles distal to chronic coronary occlusion Am J Physiol Heart Circ Physiol, March 1, 2006; 290(3): H1128 - H1135. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Merkus, B. Houweling, M. van Vliet, and D. J. Duncker Contribution of KATP+ channels to coronary vasomotor tone regulation is enhanced in exercising swine with a recent myocardial infarction Am J Physiol Heart Circ Physiol, March 1, 2005; 288(3): H1306 - H1313. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. L. Heaps, D. L. Tharp, and D. K. Bowles Hypercholesterolemia abolishes voltage-dependent K+ channel contribution to adenosine-mediated relaxation in porcine coronary arterioles Am J Physiol Heart Circ Physiol, February 1, 2005; 288(2): H568 - H576. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. J. Fountain, A. Cheong, R. Flemming, L. Mair, A. Sivaprasadarao, and D. J. Beech Functional up-regulation of KCNA gene family expression in murine mesenteric resistance artery smooth muscle J. Physiol., April 1, 2004; 556(1): 29 - 42. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Merkus, D. B. Haitsma, T.-Y. Fung, Y. J. Assen, P. D. Verdouw, and D. J. Duncker Coronary blood flow regulation in exercising swine involves parallel rather than redundant vasodilator pathways Am J Physiol Heart Circ Physiol, June 5, 2003; 285(1): H424 - H433. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
