Dual and opposing roles of presynaptic Ca2+ influx for spontaneous GABA release from rat medial preoptic nerve terminals.
2002 (English)In: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 542, no Pt 1, 131-46 p.Article in journal (Refereed) Published
Calcium influx into the presynaptic nerve terminal is well established as a trigger signal for transmitter release by exocytosis. By studying dissociated preoptic neurons with functional adhering nerve terminals, we here show that presynaptic Ca2+ influx plays dual and opposing roles in the control of spontaneous transmitter release. Thus, application of various Ca2+ channel blockers paradoxically increased the frequency of spontaneous (miniature) inhibitory GABA-mediated postsynaptic currents (mIPSCs). Similar effects on mIPSC frequency were recorded upon washout of Cd2+ or EGTA from the external solution. The results are explained by a model with parallel Ca2+ influx through channels coupled to the exocytotic machinery and through channels coupled to Ca2+-activated K+ channels at a distance from the release site.
Place, publisher, year, edition, pages
2002. Vol. 542, no Pt 1, 131-46 p.
IdentifiersURN: urn:nbn:se:umu:diva-25869DOI: 10.1113/jphysiol.2001.015610PubMedID: 12096057OAI: oai:DiVA.org:umu-25869DiVA: diva2:234474