{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,26]],"date-time":"2026-09-26T15:46:06Z","timestamp":1790437566784,"version":"4.1.0"},"reference-count":0,"publisher":"Rockefeller University Press","issue":"5","content-domain":{"domain":["rupress.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1996,5,1]]},"abstract":"<jats:p>High-voltage activated Ca channels in tiger salamander cone photoreceptors were studied with nystatin-permeabilized patch recordings in 3 mM Ca2+ and 10 mM Ba2+. The majority of Ca channel current was dihydropyridine sensitive, suggesting a preponderance of L-type Ca channels. However, voltage-dependent, incomplete block (maximum 60%) by nifedipine (0.1-100 microM) was evident in recordings of cones in tissue slice. In isolated cones, where the block was more potent, nifedipine (0.1-10 microM) or nisoldipine (0.5-5 microM) still failed to eliminate completely the Ca channel current. Nisoldipine was equally effective in blocking Ca channel current elicited in the presence of 10 mM Ba2+ (76% block) or 3 mM Ca2+ (88% block). 15% of the Ba2+ current was reversibly blocked by omega-conotoxin GVIA (1 microM). After enhancement with 1 microM Bay K 8644, omega-conotoxin GVIA blocked a greater proportion (22%) of Ba2+ current than in control. After achieving partial block of the Ba2+ current with nifedipine, concomitant application of omega-conotoxin GVIA produced no further block. The P-type Ca channel blocker, omega-agatoxin IVA (200 nM), had variable and insignificant effects. The current persisting in the presence of these blockers could be eliminated with Cd2+ (100 microM). These results indicate that photoreceptors express an L-type Ca channel having a distinguishing pharmacological profile similar to the alpha 1D Ca channel subtype. The presence of additional Ca channel subtypes, resistant to the widely used L-, N-, and P-type Ca channel blockers, cannot, however, be ruled out.<\/jats:p>","DOI":"10.1085\/jgp.107.5.621","type":"journal-article","created":{"date-parts":[[2004,5,13]],"date-time":"2004-05-13T23:51:34Z","timestamp":1084492294000},"page":"621-630","update-policy":"https:\/\/doi.org\/10.1085\/jgp.crossmarkpolicy","source":"Crossref","is-referenced-by-count":97,"title":["The dihydropyridine-sensitive calcium channel subtype in cone photoreceptors."],"prefix":"10.1085","volume":"107","author":[{"given":"M F","family":"Wilkinson","sequence":"first","affiliation":[{"name":"Neuroscience Research Group, University of Calgary, Alberta, Canada. wilkinso@acs.ucalgary.ca"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S","family":"Barnes","sequence":"additional","affiliation":[{"name":"Neuroscience Research Group, University of Calgary, Alberta, Canada. wilkinso@acs.ucalgary.ca"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"291","published-online":{"date-parts":[[1996,5,1]]},"container-title":["The Journal of general physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/rupress.org\/jgp\/article-pdf\/107\/5\/621\/1769566\/621.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/rupress.org\/jgp\/article-pdf\/107\/5\/621\/1769566\/621.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,7,26]],"date-time":"2023-07-26T11:16:48Z","timestamp":1690370208000},"score":1,"resource":{"primary":{"URL":"https:\/\/rupress.org\/jgp\/article\/107\/5\/621\/57876\/The-dihydropyridine-sensitive-calcium-channel"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1996,5,1]]},"references-count":0,"journal-issue":{"issue":"5","published-print":{"date-parts":[[1996,5,1]]}},"URL":"https:\/\/doi.org\/10.1085\/jgp.107.5.621","relation":{},"ISSN":["0022-1295","1540-7748"],"issn-type":[{"value":"0022-1295","type":"print"},{"value":"1540-7748","type":"electronic"}],"subject":[],"published":{"date-parts":[[1996,5,1]]}}}