AJP - Heart and Circulatory Physiology, Vol 272, Issue 1 256-H262, Copyright © 1997 by American Physiological Society

ARTICLES

Effect of nitric oxide and potassium channel agonists and inhibitors on basilar artery diameter

C. G. Sobey and F. M. Faraci
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242, USA.

The first goal of this study was to examine the hypothesis that dilatation of the basilar artery in response to activation of ATP-sensitive K+ channels is mediated by nitric oxide (NO). Diameter of the basilar artery (209 +/- 5 microns, mean +/- SE) was measured using a cranial window in anesthetized rats. Aprikalim (a direct activator of ATP-sensitive K+ channels) dilated the basilar artery under control conditions. Inhibition of endogenous NO production with NG-nitro-L-arginine (L-NNA, 10(-4) M) did not alter responses to aprikalim. The second goal was to determine whether vasodilatation in response to NO is dependent on activation of calcium-activated K+ channels. Tetraethylammonium (TEA, 10(-3) M), an inhibitor of calcium-activated K+ channels, did not affect dilator responses to sodium nitroprusside (an NO donor) under control conditions. Responses to nitroprusside (10(-8) and 10(-7) M) were augmented more than twofold during application of L-NNA. In the presence of L-NNA, the augmented portion of the response to nitroprusside was inhibited by TEA and iberiotoxin (5 x 10(-8) M, a highly selective inhibitor of calcium-activated K+ channels), but it was not inhibited by glibenclamide (10(-6) M), an inhibitor of ATP-sensitive K+ channels. These findings suggest that dilator responses of the basilar artery to an activator of ATP-sensitive potassium channels are not mediated by NO. Calcium-activated K+ channels may not normally contribute to dilator responses of the basilar artery to nitroprusside. The effects of TEA and iberiotoxin suggest that when endogenous production of NO is inhibited, sodium nitroprusside causes the opening of calcium-activated K+ channels, contributing to an augmented vasodilator response.

This article has been cited by other articles:

				Y. Shi, X. Wang, K. H. Chon, and W. A. Cupples Tubuloglomerular feedback-dependent modulation of renal myogenic autoregulation by nitric oxide Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2006; 290(4): R982 - R991. [Abstract] [Full Text] [PDF]

				J. Yang, J. W. Clark, R. M. Bryan, and C. S. Robertson Mathematical modeling of the nitric oxide/cGMP pathway in the vascular smooth muscle cell Am J Physiol Heart Circ Physiol, August 1, 2005; 289(2): H886 - H897. [Abstract] [Full Text] [PDF]

				F. M. Faraci, C. G. Sobey, S. Chrissobolis, D. D. Lund, D. D. Heistad, and N. L. Weintraub Arachidonate dilates basilar artery by lipoxygenase-dependent mechanism and activation of K+ channels Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2001; 281(1): R246 - R253. [Abstract] [Full Text] [PDF]

				C. G. Sobey Potassium Channel Function in Vascular Disease Arterioscler. Thromb. Vasc. Biol., January 1, 2001; 21(1): 28 - 38. [Abstract] [Full Text] [PDF]

				T. Horiuchi, H. H. Dietrich, S. Tsugane, R. G. Dacey Jr, C. G. Sobey, and F. M. Faraci Role of Potassium Channels in Regulation of Brain Arteriolar Tone : Comparison of Cerebrum Versus Brain Stem Editorial Comment: Comparison of Cerebrum Versus Brain Stem Stroke, January 1, 2001; 32(1): 218 - 224. [Abstract] [Full Text] [PDF]

				S. Chrissobolis, J. Ziogas, Y. Chu, F. M. Faraci, and C. G. Sobey Role of inwardly rectifying K+ channels in K+-induced cerebral vasodilatation in vivo Am J Physiol Heart Circ Physiol, December 1, 2000; 279(6): H2704 - H2712. [Abstract] [Full Text] [PDF]

				L. Quan, C. G. Sobey, Z. S. Katusic, and V. G. Khurana Selective Effects of Subarachnoid Hemorrhage on Cerebral Vascular Responses to 4-Aminopyridine in Rats Editorial Comment Stroke, October 1, 2000; 31(10): 2460 - 2465. [Abstract] [Full Text] [PDF]

				C.-W. Sun, J. R. Falck, H. Okamoto, D. R. Harder, and R. J. Roman Role of cGMP versus 20-HETE in the vasodilator response to nitric oxide in rat cerebral arteries Am J Physiol Heart Circ Physiol, July 1, 2000; 279(1): H339 - H350. [Abstract] [Full Text] [PDF]

				C. G. Sobey and L. Quan Impaired cerebral vasodilator responses to NO and PDE V inhibition after subarachnoid hemorrhage Am J Physiol Heart Circ Physiol, November 1, 1999; 277(5): H1718 - H1724. [Abstract] [Full Text] [PDF]

				C. G. Sobey, J. D. Moffatt, T. M. Cocks, and H. A. Kontos Evidence for Selective Effects of Chronic Hypertension on Cerebral Artery Vasodilatation to Protease-Activated Receptor-2 Activation • Editorial Comment Stroke, September 1, 1999; 30(9): 1933 - 1941. [Abstract] [Full Text] [PDF]

				F. A. Sehba, W. H. Ding, I. Chereshnev, J. B. Bederson, and J. P. Muizelaar Effects of S-Nitrosoglutathione on Acute Vasoconstriction and Glutamate Release After Subarachnoid Hemorrhage • Editorial Comment Stroke, September 1, 1999; 30(9): 1955 - 1961. [Abstract] [Full Text] [PDF]

				M. D. S. Frame Conducted signals within arteriolar networks initiated by bioactive amino acids Am J Physiol Heart Circ Physiol, March 1, 1999; 276(3): H1012 - H1021. [Abstract] [Full Text] [PDF]

				W. M. Armstead Relationship among NO, the KATP channel, and opioids in hypoxic pial artery dilation Am J Physiol Heart Circ Physiol, September 1, 1998; 275(3): H988 - H994. [Abstract] [Full Text] [PDF]

				C. G. Sobey, T. M. Cocks, and Z. S. Katusic Activation of Protease-Activated Receptor-2 (PAR-2) Elicits Nitric Oxide–Dependent Dilatation of the Basilar Artery In Vivo • Editorial Comment Stroke, July 1, 1998; 29(7): 1439 - 1444. [Abstract] [Full Text] [PDF]

				E. Thorin, P. L. Huang, M. C. Fishman, and J. A. Bevan Nitric Oxide Inhibits {alpha}2-Adrenoceptor–Mediated Endothelium-Dependent Vasodilation Circ. Res., June 29, 1998; 82(12): 1323 - 1329. [Abstract] [Full Text] [PDF]

				W. G. Mayhan and K. P. Patel Treatment with dimethylthiourea prevents impaired dilatation of the basilar artery during diabetes mellitus Am J Physiol Heart Circ Physiol, June 1, 1998; 274(6): H1895 - H1901. [Abstract] [Full Text] [PDF]

				F. M. Faraci, C. D. Sigmund, E. G. Shesely, N. Maeda, and D. D. Heistad Responses of carotid artery in mice deficient in expression of the gene for endothelial NO synthase Am J Physiol Heart Circ Physiol, February 1, 1998; 274(2): H564 - H570. [Abstract] [Full Text] [PDF]

				F. M. FARACI and D. D. HEISTAD Regulation of the Cerebral Circulation: Role of Endothelium and Potassium Channels Physiol Rev, January 1, 1998; 78(1): 53 - 97. [Abstract] [Full Text] [PDF]

				E. Thorin, T.-D. Nguyen, A. Bouthillier, and F. M. Faraci Control of Vascular Tone by Endogenous Endothelin-1 in Human Pial Arteries • Editorial Comment Stroke, January 1, 1998; 29(1): 175 - 180. [Abstract] [Full Text] [PDF]

				C. G. Sobey and F. M. Faraci Effects of a Novel Inhibitor of Guanylyl Cyclase on Dilator Responses of Mouse Cerebral Arterioles Stroke, April 1, 1997; 28(4): 837 - 843. [Abstract] [Full Text]

				M. Yu, C.-W. Sun, K. G. Maier, D. R. Harder, and R. J. Roman Mechanism of cGMP contribution to the vasodilator response to NO in rat middle cerebral arteries Am J Physiol Heart Circ Physiol, May 1, 2002; 282(5): H1724 - H1731. [Abstract] [Full Text] [PDF]