Synaptotagmin-2 Is Essential for Survival and Contributes to Ca²⁺ Triggering of Neurotransmitter Release in Central and Neuromuscular Synapses

Paired-pulse facilitation. A, Representative traces of paired-pulse stimuli induced synaptic responses in WT and synaptotagmin-2 KO NMJ. B, Paired-pulse ratio of evoked EPP when given two stimuli at different interstimulus intervals ranging from 20 to 100 ms. The numbers of recordings are indicated in parentheses. Error bars indicate SEM. **p < 0.01; ***p < 0.001.