Hyperpolarizing membrane potential changes in a cloned monkey kidney cell line

Electrophysiological properties of a cloned monkey kidney cell line, JTC-12, were studied. The mean resting potential and input resistance were -15.3 mV and 78 M omega, respectively. Spontaneous hyperpolarizations with increased membrane conductance were observed. Similar hyperpolarization could be elicited by mechanical and electrical stimulations. The mean reversal potential of these hyperpolarizations was -72.7 mV. Hyperpolarization could be also elicited in a chloride-free solution. These data indicate that: JTC-12 cells exhibit spontaneous and induced hyperpolarizations, and occurrence of hyperpolarization is related to an increase in membrane permeability to potassium ions.