Responses to light of solitary rod photoreceptors isolated from tiger salamander retina.

Single, isolated rod photoreceptors were obtained by enzymatic dissociation of the tiger salamander (Ambystoma tigrinum) retina. These solitary cells retained the morphological features of rods of the intact retina and could be maintained in culture for several days. When impaled with micropipettes for electrophysiological recording, dark-adapted solitary rods had during darkness a resting potential of approximately -45 mV and a steady-state slope resistance of 500 Momega at rest. The current-voltage relationship showed both inward- and outward-going rectification. The responses to light of solitary rods were similar to those recorded from rods in the intact retina stimulated with large-diameter spots of light. The reversal potential of the light response of solitary rods was near 0 mV when measured in either the inner or outer segment.