A comparison of synaptic protein localization in hippocampal mossy fiber terminals and neurosecretory endings of the neurohypophysis using the cryo-immunogold technique.

摘要: In central synapses synaptic vesicle docking and exocytosis occurs at morphologically specialized sites (active zones) requires the interaction of specific proteins in formation a SNARE complex. contrast, neurosecretory terminals lack active zones. Using cryo-immunogold technique we analyzed localization complex This was compared to identical terminals. addition vesicular granular investigated. Synaptic vesicles rat hippocampal mossy fiber microvesicles neurohypophysis contained common VAMP II (a v-SNARE), SV2, rab3A, N-type Ca2+ channels. Only minor immunolabeling for these observed granules. These results support notion close functional identity from endings vesicles. The pool channels may serve their stimulation-induced translocation into plasma membrane. We find increased labeling II, SNAP-25, rab3A zones synapses. Labeling release is by far highest Bassoon, high molecular weight protein zone. pattern implies an association Bassoon with presynaptic dense projections. absent reveal scattered distribution over competence zone selective not primarily result its contents but rather preformation projections as structural guides exocytosis.