VOLTAGE-DEPENDENT SWITCH IN THE ACTIVITY MODE OF THE K-TERMINALS( CHANNEL IN PRESYNAPTIC NERVE)

THE bursting K+ channel is the most common channel in fused Torpedo pr esynaptic nerve terminals. It possesses the property of 'statistical m emory', demonstrated by non-random probability of channel opening. We examined the voltage dependence of the statistical memory and report t hat removal of channel inactivation by hyperpolarization abolishes it. Addition of the potassium channel blocker 4-aminopyridine to the bath solution led to disappearance of statistical memory, while raising ex tracellular potassium concentration had the opposite effect. Another c ommon channel at Torpedo nerve terminals which is a non-selective chan nel did not exhibit statistical memory. We conclude that statistical m emory is a channel-specific phenomenon and speculate regarding its pos sible role in cellular and network properties of the nervous system.