Disturbances in autoregulatory responses of rat pial arteries by sulfonylureas.
It was aimed to test the role of ATP-sensitive K+ channels in the autoregulatory response of cerebral arterioles in vivo. Changes in pial arterial caliber (mean, 43.2 +/- 2.3 microns in diameter) in response to changes in systemic arterial blood pressure (mean, 104.3 +/- 1.4 mmHg) were observed directly through closed cranial windows in anesthetized normotensive rats. During superfusion with vehicle, pial arterial caliber automatically increased in response to hypotension induced by arterial bleeding into a reservoir and decreased on reverse of arterial blood pressure by infusion of blood. After pretreatment with sulfonylureas, glibenclamide (1 and 3 microM) and glipizide (30 and 100 microM), arteriolar dilatation and constriction observed during hypotension and its reverse were disturbed. A similarity was evidenced when hypotension was induced by sodium nitroprusside (750 nmol kg-1min-1, i.v.). Cromakalim, a K+ channel opener, exerted a concentration-dependent vasodilatation of the pial artery and its effect was antagonized by glibenclamide. These data suggest that the endogenous glibenclamide-sensitive K+ channel opener is involved in the modulation of cerebral microvascular autoregulation.
Lee
W S
WS
Department of Pharmacology, College of Medicine, Pusan National University, Korea.
Kwon
Y J
YJ
Yu
S S
SS
Rhim
B Y
BY
Hong
K W
KW
D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002536:Cerebral Arteries / Q000187:drug effects / Q000502:physiology; D005913:Glipizide / Q000494:pharmacology*; D005905:Glyburide / Q000494:pharmacology*; D010841:Pia Mater / Q000098:blood supply*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D005905:Glyburide; D005913:Glipizide