CAPSAICIN BLOCKS SYNAPTICALLY ACTIVATED POTASSIUM CONDUCTANCE IN SNAIL NEURON

The effect of capsaicin was studied on non-cholinergic inhibitory postsynaptic currents (IPSC). The experiments were performend on an identified snail neuron using the single electrode voltage-clamp technique. The IPSC decayed with a bi-exponential time course. Capsaicin (200 .mu.M) reversibly blocked both components of the transmitter-activated K conductance similar to other K channel blockers such as Ba2+, quinine or 4-aminopyridine. Externally applied TEA+ [tetraethylammonium] exclusively attenuated the slow phase. Capsaicin prolonged the action potential duration and decreased the membrane outward current in the postsynaptic neuron.