{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,13]],"date-time":"2026-03-13T18:02:37Z","timestamp":1773424957159,"version":"3.50.1"},"reference-count":0,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[1995,8,1]],"date-time":"1995-08-01T00:00:00Z","timestamp":807235200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["The Journal of Physiology"],"published-print":{"date-parts":[[1995,8]]},"abstract":"<jats:p>1. The effects of the calcium channel blockers, funnel\u2010web spider toxin (FTX), omega\u2010agatoxin IVA (omega\u2010Aga IVA) and omega\u2010conotoxin GVIA (omega\u2010CgTX), were tested on transmitter release and presynaptic currents in frog motor nerve endings. 2. Evoked transmitter release was blocked by FTX (IC50 = 0.02 microliter ml\u20101) and omega\u2010CgTX (1 microM) but was not affected by omega\u2010Aga IVA (0.5 microM). When FTX (0.1 microliter ml\u20101) was assayed on spontaneous release either in normal Ringer solution or in low Ca(2+)\u2010high Mg2+ solution, it was found not to affect miniature endplate potential (MEPP) amplitude but to increase MEPP frequency by approximately 2\u2010fold in both conditions. 3. Presynaptic calcium currents (ICa), measured by the perineurial technique in the presence of 10 mM tetraethylammonium chloride (TEA) and 200 microM BaCl2 to block K+ currents, were blocked by omega\u2010CgTX (5 microM), partially blocked by FTX (1 microliter ml\u20101) and not affected by omega\u2010Aga IVA (0.5 microM). 4. The presynaptic calcium\u2010activated potassium current (IK(Ca)) measured by the perineurial technique in the presence of 0.5 microM 3,4\u2010aminopyridine (DAP) to block voltage\u2010dependent K+ currents, was strongly affected by charybdotoxin (ChTX) (300 nM) and completely abolished by BaCl2 (200 microM). This current was also blocked by omega\u2010CgTX (5 microM) and by CdCl2 (200 microM) but was not affected by FTX (1 microliter ml\u20101). The blockade by omega\u2010CgTX could not be reversed by elevating [Ca]o to 10 mM. 5. The results suggest that in frog synaptic terminals two omega\u2010CgTX\u2010sensitive populations might coexist. The transmitter release process seems to be mediated by calcium influx through a omega\u2010CgTX\u2010 and FTX\u2010sensitive population.<\/jats:p>","DOI":"10.1113\/jphysiol.1995.sp020845","type":"journal-article","created":{"date-parts":[[2014,12,17]],"date-time":"2014-12-17T10:19:57Z","timestamp":1418811597000},"page":"695-706","source":"Crossref","is-referenced-by-count":54,"title":["Effects of Ca2+ channel blockers on transmitter release and presynaptic currents at the frog neuromuscular junction."],"prefix":"10.1113","volume":"486","author":[{"given":"E","family":"Katz","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"P A","family":"Ferro","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"B D","family":"Cherksey","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M","family":"Sugimori","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R","family":"Llin\u00e1s","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"O D","family":"Uchitel","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[1995,8]]},"container-title":["The Journal of Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1113%2Fjphysiol.1995.sp020845","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/jphysiol.1995.sp020845","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,25]],"date-time":"2023-10-25T14:48:09Z","timestamp":1698245289000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/jphysiol.1995.sp020845"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1995,8]]},"references-count":0,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1995,8]]}},"alternative-id":["10.1113\/jphysiol.1995.sp020845"],"URL":"https:\/\/doi.org\/10.1113\/jphysiol.1995.sp020845","archive":["Portico"],"relation":{},"ISSN":["0022-3751","1469-7793"],"issn-type":[{"value":"0022-3751","type":"print"},{"value":"1469-7793","type":"electronic"}],"subject":[],"published":{"date-parts":[[1995,8]]}}}