ATP-sensitive potassium channels in the basilar artery during chronic hypertension.

Abstract

We examined the hypothesis that dilatation of the basilar artery in response to activation of ATP-sensitive potassium channels is impaired in stroke-prone spontaneously hypertensive rats (SHRSP). Changes in basilar artery diameter in response to aprikalim, a direct activator of ATP-sensitive potassium channels, were measured in anesthetized SHRSP and normotensive Wistar-Kyoto (WKY) rats through a cranial window. Topical application of aprikalim increased basilar artery diameter in WKY rats. Glibenclamide, a selective inhibitor of ATP-sensitive potassium channels, abolished aprikalim-induced vasodilatation. Thus, ATP-sensitive potassium channels are functional in the basilar artery of WKY rats in vivo. Aprikalim (10(-6) mol/L) dilated the basilar artery by 31 +/- 5% (mean +/- SEM) in WKY rats but only 5 +/- 1% in SHRSP. The concentration-response curve to aprikalim in SHRSP was significantly shifted to the right, but the response to the highest concentration of aprikalim (10(-5.5) mol/L) was similar in SHRSP and WKY rats. Vasodilatation in response to norepinephrine was also impaired in SHRSP. Dilator responses of the basilar artery to forskolin, a direct activator of adenylate cyclase, and nitroprusside, a direct activator of guanylate cyclase, were normal in SHRSP. The findings suggest that dilatation of the basilar artery in response to direct activation of ATP-sensitive potassium channels is impaired in SHRSP compared with WKY rats in vivo.

• Authors: T Kitazono, D D Heistad, F M Faraci
• Journal: Hypertension (Dallas, Tex. : 1979) (Hypertension) Vol. 22 Issue 5 Pg. 677-81 (Nov 1993) ISSN: 0194-911X [Print] United States
• PMID: 8225527 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Antihypertensive Agents
• Picolines
• Potassium Channels
• Pyrans
• Nitroprusside
• Colforsin
• aprikalim
• Adenosine Triphosphate
• Norepinephrine

Topics

• Adenosine Triphosphate (pharmacology)
• Animals
• Antihypertensive Agents (pharmacology)
• Basilar Artery (drug effects, physiology, physiopathology)
• Cerebrovascular Disorders (genetics)
• Colforsin (pharmacology)
• Dose-Response Relationship, Drug
• Hypertension (genetics, physiopathology)
• In Vitro Techniques
• Male
• Models, Cardiovascular
• Muscle, Smooth, Vascular (drug effects, physiology, physiopathology)
• Nitroprusside (pharmacology)
• Norepinephrine (pharmacology)
• Picolines (pharmacology)
• Potassium Channels (drug effects, metabolism)
• Pyrans (pharmacology)
• Rats
• Rats, Inbred SHR
• Rats, Inbred WKY
• Vasodilation (drug effects)