Fig. 6.

Modulation of terminal [Ca²⁺]_i rises by pulse duration.Aa, Time sequence of OG5 pseudocolor images from the synaptic terminal region of an RBC. The first panelcorresponds to the fourth image in a series taken at rest (cycle time, 52 msec). A 50 msec depolarization to 0 mV, applied immediately after the end of this image (time, 156–206 msec), elicits substantial increases in fluorescence throughout the terminals that begins to decay when the membrane potential returns to V_h.Ab, Ac, Temporal evolution of the percent of fluorescence change and the correspondingI_Ca for the experiment shown inAa. Ba, Bb, Temporal evolution of the percent of fluorescence change and the correspondingI_Ca for a 250 msec depolarization in the same cell. Note that for a given pulse duration, the pulse-evoked changes in fluorescence have similar magnitudes and time courses in the two terminals analyzed. Internal solution was CsGlu (200 μm OG5, no EGTA).