Abstract
Potassium channels appear to be present in most cells and play an important role in regulation of the membrane potential. In cerebral blood vassels, four different potassium channels have been described: ATP-sensitive potassium channels, large conductance calcium-activated potassium channels, voltage-dependent patassium chonnels, and inward rectifier potassium channels. Activation of the ATP-sensitive and large conductance calcium-activated postassium channels appears to play an important role in the dilatory responses of cerebral blood vessels to diverse endogenous stimuli. The influence of these potassium channels is altered in disease states such as hypertension, diabetes, and atherosclerosis. It has been reported that an activator of ATP-sensitive potassiun channels effectively dilated spastic cerebral arteries following experimental subarachnoid hemorrhage. We have recently demonstrated that intracar-otid infusion of ATP-sensitive potassium channel openers can reduce ischemic neuronal damage in a focal ischemia model of the rats. It is possible therefore that modulation of the activity of potassium channels could provide a new therapeutic strategy for brain infarction and subarachnoid hemorrhage.
