Synaptic transmission from rods to bipolar cells in the tiger salamander retina

Synaptic transmission between rods and depolarizing bipolar cells (DBC) was studied by using simultaneous recording techniques in the living retinal slice preparation. Current injection into the rod elicited a sign-inverting, sustained voltage change in the DBC. Voltage "tails" after the termination of a bright flash were observed in dark-adapted rods and DBC but not in cones. These simultaneously recorded voltage tails were used to isolate the rod input from the cone input and to study the input-output relation of the rod-DBC synapse. Within the voltage range between 0 and -10 mV from the rod dark potential (-39 +/- 1.2 mV), the input-output relation of the rod-DBC was approximately linear, with an estimated gain of about 3.7.