Spectrin (beta SpII Sigma 1) is an essential component of synaptic transmission

The cellular mechanism that underlies the regulated release of synaptic ves icles during neurotransmission is not fully known. Our previous data has sh own that brain spectrin (alpha SpII Sigma 1/beta SpII Sigma 1)(2) is locali zed in axons and nerve terminals and we have shown that the beta subunit (b eta SpII Sigma 1) contains a synapsin-binding domain capable of interacting with synapsin and small synaptic vesicles in vitro and in vivo. These find ings suggested a role for brain beta-spectrin in synaptic neurotransmission To examine this possibility further, peptide-specific antibodies directed against epitopes within the synapsin-binding domain of brain beta-spectrin, or against flanking regions, were injected into the presynaptic neuron of synaptically paired rat hippocampal neurons in culture. Here, we show that the antibodies directed against the synapsin-binding domain specifically bl ocked synaptic neurotransmission. (C) 2000 Published by Elsevier Science B. V. All rights reserved.