Solitary horizontal cells in culture--I. Their electrical properties

Membrane properties of solitary horizontal cells were examined under current- and voltage-clamp conditions. The resting membrane potential was mainly determined by K ions. The cells produced all-or-none action potentials and showed non-linear current-voltage relationships with inward- and outward-going rectification. Pharmacological and ion-substitution experiments under voltage-clamp conditions revealed that the ionic current was separated into at least four components; a Ca current and three types of K currents (a K current through an anomalous rectifier, a transient outward current, and a maintained outward current). The action potentials and the non-linear current-voltage relationships of solitary horizontal cells were explained from these ionic currents.