{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,7]],"date-time":"2025-07-07T05:26:31Z","timestamp":1751865991683},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"2","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1994,12,1]]},"abstract":"<jats:p>Tityustoxin (TsTX), a toxin obtained from the venom of the Brazilian scorpion Tityus serrulatus, stimulates Na+ influx through tetrodotoxin (TTX)-sensitive Na+ channels which, in turn, promotes both Ca(2+)-dependent and Ca(2+)-independent release of glutamate from rat cerebrocortical synaptosomes. The level of Ca(2+)-dependent glutamate release after addition of 0.5 microM TsTX is greater than that produced by a maximally depolarizing concentration of KCl. This effect of TsTX, which is entirely dependent on Na+ entry, suggests that Na+ has a role in modulating Ca2+ entry and glutamate release that is not simply related to membrane depolarization. In order to investigate possible modulatory role(s) of Na+ on Ca(2+)-dependent glutamate release, we compared the effects of TsTX with those of KCl and the Na+ ionophore gramicidin D. When used alone, 100 nM gramicidin D produced a larger increase in intrasynaptosomal free Na+ than did 0.5 microM TsTX, and a similar rise in intrasynaptosomal free Ca2+, but was much less effective in promoting glutamate release. Even the combination of membrane depolarization (by 33 mM KCl) and elevation of intrasynaptosomal free Na+ (by 100 nM gramicidin) was still less effective than TsTX at causing Ca(2+)-dependent glutamate release. These data suggest that localized Na+ entry, through TTX-sensitive Na+ channels, exerts a modulatory role on Ca(2+)-dependent glutamate release from nerve endings in the cerebral cortex.<\/jats:p>","DOI":"10.1042\/bj3040353","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T21:40:39Z","timestamp":1439242839000},"page":"353-357","update-policy":"http:\/\/dx.doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Modulation of Ca2+-stimulated glutamate release from synaptosomes by Na+ entry through tetrodotoxin-sensitive channels"],"prefix":"10.1042","volume":"304","author":[{"given":"M A","family":"Romano-Silva","sequence":"first","affiliation":[{"name":"Department of Biochemistry and Immunology, and Department of Pharmacology, ICB, Universidade Federal de Minas Gerais, Caixa Postal 2486, 30161-Belo Horizonte, MG, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M V","family":"Gomez","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Immunology, and Department of Pharmacology, ICB, Universidade Federal de Minas Gerais, Caixa Postal 2486, 30161-Belo Horizonte, MG, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M J","family":"Brammer","sequence":"additional","affiliation":[{"name":"\u2020Department of Neuroscience, Institute of Psychiatry, DeCrespigny 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\/304\/2\/353\/725498\/bj3040353.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/304\/2\/353\/725498\/bj3040353.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,23]],"date-time":"2021-11-23T23:19:07Z","timestamp":1637709547000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/304\/2\/353\/31534\/Modulation-of-Ca2-stimulated-glutamate-release"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1994,12,1]]},"references-count":0,"journal-issue":{"issue":"2","published-print":{"date-parts":[[1994,12,1]]}},"URL":"https:\/\/doi.org\/10.1042\/bj3040353","relation":{},"ISSN":["0264-6021","1470-8728"],"issn-type":[{"value":"0264-6021","type":"print"},{"value":"1470-8728","type":"electronic"}],"subject":[],"published":{"date-parts":[[1994,12,1]]}}}