Evidence for Ca2+-activated K+ Conductance in Cat Spinal Motoneurons from Intracellular EGTA Injections

Abstract

Ethylene glycol bis-(β-aminoelhyl ether)-N,N′-tetraacetic acid, injected by iontophoresis from triple-barrelled intracellular micropipettes, consistently raised the membrane resistance and depressed the post-spike after hyperpolarization (AHP), but did not slow the falling phase of the action potential. [Ca²⁺]_i-activated K⁺ channels appear to play a significant role in the genesis of the AHP and in the control of the resting potential, but not in the repolarization phase of the action potential.