The slow phase of the acetylcholine response in isolated neurons of the gastropod mollusc, Planorbarius corneus

Abstract 1. 1. The slow phase of the acetylcholine current response has been studied in identified isolated neurons of Planorbarius corneus . 2. 2. The reversal potential of the response was found to be equal to −92 mV (conf. lim. −85 mV to −99 mV); it shifted for 14 mV to more depolarized levels of the membrane potential when the external [K + ] was doubled and for 28–30 mV when the external [K + ] was increased four-fold. 3. 3. The voltage-current relationship of the potassium-dependent acetylcholine response was found to be non-linear, the conductance decreasing with membrane hyperpolarization. 4. 4. The initial part of the potassium-dependent acetylcholine response was found to be approximated by kt 3 , where k = apparent rate constant, t = time. Q 10 for the apparent constant k was found to be equal to 15 (conf. lim. 12–18).