{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T22:16:29Z","timestamp":1777500989282,"version":"3.51.4"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"2","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1993,12,1]]},"abstract":"<jats:p>PhTX2, one of the components of the venom of the South American spider Phoneutria nigriventer, inhibits the closure of voltage-sensitive Na+ channels. Incubation of cerebral-cortical synaptosomes with PhTX2 causes a rapid increase in the intrasynaptosomal free Ca2+ concentration and a dose-dependent release of glutamate. This release is made up of a slow component, which appears to be due to reversal of Na(+)-dependent glutamate uptake, and more rapid component that is dependent on the entry of extrasynaptosomal Ca2+. It has previously been shown that membrane depolarization using KCl can cause rapid Ca(2+)-dependent release of glutamate from synaptosomes. This requires Ca2+ entry through a specific type of Ca2+ channel that is sensitive to Aga-GI, a toxic component of the venom of the spider Agelenopsis aperta. We have compared the effects of PhTX2 and KCl on elevation of intrasynaptosomal free Ca2+ and glutamate release, and a number of differences have emerged. Firstly, PhTX2-mediated Ca2+ influx and glutamate release, but not those caused by KCl, are inhibited by tetrodotoxin. Secondly, KCl produces a clear additional increase in Ca2+ and glutamate release following those elicited by PhTX2. Finally, 500 microM MnCl2 abolishes PhTX2-mediated, but not KCl-mediated, glutamate release. These findings suggest that more than one mechanism of Ca2+ entry may be coupled to glutamate release from nerve endings.<\/jats:p>","DOI":"10.1042\/bj2960313","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T21:35:38Z","timestamp":1439242538000},"page":"313-319","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":62,"title":["Rat cortical synaptosomes have more than one mechanism for Ca2+ entry linked to rapid glutamate release: studies using the <i>Phoneutria nigriventer<\/i> toxin PhTX2 and potassium depolarization"],"prefix":"10.1042","volume":"296","author":[{"given":"M A","family":"Romano-Silva","sequence":"first","affiliation":[{"name":"Department of Biochemistry and Immunology"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R","family":"Ribeiro-Santos","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Immunology"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A M","family":"Ribeiro","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Immunology"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M V","family":"Gomez","sequence":"additional","affiliation":[{"name":"Deparment of Pharmacology, ICB, Universidade Federal de Minas Gerais, Caixa Postal 2486, 30161-Belo Horizonte, MG, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C R","family":"Diniz","sequence":"additional","affiliation":[{"name":"Centro de Pesquisa e Desenvolvimento, Funda\u00e7\u00e3o Ezequiel Dias, 30161-Belo Horizonte, MG, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M N","family":"Cordeiro","sequence":"additional","affiliation":[{"name":"Centro de Pesquisa e Desenvolvimento, Funda\u00e7\u00e3o Ezequiel Dias, 30161-Belo Horizonte, MG, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M J","family":"Brammer","sequence":"additional","affiliation":[{"name":"Department of Neuroscience, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/296\/2\/313\/611825\/bj2960313.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/296\/2\/313\/611825\/bj2960313.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,23]],"date-time":"2021-11-23T21:09:37Z","timestamp":1637701777000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/296\/2\/313\/30266\/Rat-cortical-synaptosomes-have-more-than-one"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1993,12,1]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1993,12,1]]}},"URL":"https:\/\/doi.org\/10.1042\/bj2960313","relation":{},"ISSN":["0264-6021","1470-8728"],"issn-type":[{"value":"0264-6021","type":"print"},{"value":"1470-8728","type":"electronic"}],"subject":[],"published":{"date-parts":[[1993,12,1]]}}}