Overexpression of synaptophysin enhances neurotransmitter secretion at Xenopus neuromuscular synapses

摘要: Previous studies have suggested the importance of synaptophysin (p38), a major integral membrane protein synaptic vesicle, in transmitter secretion, but few directly addressed its functional role at intact synapses. In present study, injection synthetic mRNA for into one early blastomeres Xenopus embryo resulted elevated expression 1 and 2 d embryos cultured spinal neurons derived from injected blastomere, as shown by immunocytochemistry. At neuromuscular synapses made overexpressing [p38(+)] cell cultures, spontaneous currents (SSCs) showed markedly higher frequency, compared to control This increase frequency was not accompanied change mean amplitude or distribution SSCs, suggesting that is involved determining size quanta. The impulse- evoked (ESCs) p38(+) increased well reduced fluctuation delay onset ESCs. Under high-frequency tetanic stimulation 5 Hz, rate tetanus-induced depression faster neurons. Taken together, these results suggest late steps affecting probability vesicular exocytosis and/or number vesicles initially docked active zone.