CEREBRAL VASCULAR SMOOTH-MUSCLE POTASSIUM CHANNELS AND THEIR POSSIBLEROLE IN THE MANAGEMENT OF VASOSPASM

One of the promising therapeutic uses of the potassium channel openers is in the management of cerebral vasospasm, a prolonged vasoconstrict ion of major cerebral arteries which follows aneurysmal subarachnoid h aemorrhage. In this review, we first summarize the properties of potas sium channels in cerebral vascular smooth muscle. Calcium-activated an d ATP-dependent potassium channels are the major potassium channels id entified in the cerebrovascular smooth muscle and both are believed to play a role in the regulation of cerebrovascular smooth muscle lone. The calcium-activated potassium channels can be activated by depolariz ation, bp elevation of internal calcium and by some vasodilators. Some neuropeptides and potassium channel openers open the ATP-dependent po tassium channels and produce vasodilation. We then review the effects of both synthetic and endogenous potassium channel openers in the cere brovascular system, discuss their efficacy in the management of models of cerebrovascular spasm, and outline the clinical promise of these a gents.