Fig. 9.

PPF is not affected after synapsin neutralization under low release probability. Paired stimuli were elicited at various interpulse intervals before (○) and 360–480 min after (●) the intraneuronal injection of G423 antibody in the presence of either normal (Ca/Mg = 0.42; A) or low (Ca/Mg = 0.14;B) Ca²⁺-containing medium. The extent of paired-pulse facilitation (means ± SEM from 4 experiments in A and from 3 experiments in B) was calculated at the indicated interpulse intervals. Note that values reported at the 40 sec interval have been collected at the basal stimulation rate (0.025 Hz). Statistical comparison of PPF extent before and after synapsin neutralization: *p < 0.01; **p< 0.001.