Different types of potassium channels underlie the long afterhyperpolarization in guinea-pig sympathetic and enteric neurons

Abstract

Ca2+-activated K+ channels play an important role in the control of neuronal excitability via the generation of the afterhyperpolarization. While both small and large conductance Ca 2+-activated K+ channels underlie afterhyperpolarizations in different neuron types, the role of intermediate conductance Ca 2+-activated K+ channels (IKCa) in the generation of afterhyperpolarizations remains unclear. The effects of blockade of IKCa on guinea pig coeliac and ileal myenteric neurons were studied using single microelectrode current and voltage clamp. In coeliac neurons, TRAM-39, a selective blocker of IKCa, depressed the amplitude of the prolonged conductance underlying the slow afterhyperpolariza..