Figure 1

Retinal bipolar cells isolated from old-aged zebrafish exhibited no changes in their brief release properties relative to middle-aged fish. (A,B) Ca²⁺ current (I) recorded from the synaptic terminal of a bipolar neuron isolated from middle-aged (MA; panel (A)) and older-aged (OA; panel (B)) zebrafish in response to a voltage-clamp pulse (V) from −60 mV to −15 mV for 10 ms. The sinusoidal voltage stimulus used to monitor membrane capacitance (C_m) and series conductance (G_s) is visible at the beginning and end of the voltage trace. Below the traces are the resulting values of C_m for MA (filled circles) vs. OA (open circles) fish and of G_s for MA (filled diamonds) vs. OA (open diamond) fish before and after the activation of the Ca²⁺ current. (C,D) Average calcium current (C) and capacitance (D) in response to a voltage-clamp pulse (V) from −60 mV to −15 mV for 10 ms that was obtained from bipolar neurons of MA (A) and OA (B) zebrafish. n = 20 MA, seven animals: n = 12 OA bpcs; nine animals. Individual values of Ca²⁺ current capacitance measurements are shown in Supplementary Figure S2.