{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T12:52:57Z","timestamp":1777467177812,"version":"3.51.4"},"reference-count":0,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[1991,11,1]],"date-time":"1991-11-01T00:00:00Z","timestamp":688953600000},"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":[[1991,11]]},"abstract":"<jats:p>1. L\u2010type calcium channels in embryonic chick heart ventricle have voltage\u2010dependent, time\u2010variant kinetics when they conduct inward currents carried by 20 mM\u2010Ba2+. Depolarizing the membrane from \u201020 to 20 mV increases mean open time from 1.4 to 4.2 ms. Mean open time increases monotonically with voltage. The single\u2010channel conductance, 18 +\/\u2010 2 pS, is approximately linear over this voltage range, and the extrapolated reversal potential is 38 +\/\u2010 5 mV. 2. In cell\u2010attached patches with five or more L\u2010type Ca2+ channels in the patch, the currents elicited by 500 ms depolarizing steps, from a \u201080 mV holding potential, inactivate rapidly and have large tail currents. In the same patch, currents from a \u201040 mV holding potential are smaller, inactivate more slowly, and have practically no tail currents. 3. In cell\u2010attached patches containing one of two L\u2010type Ca2+ channels, currents from \u201080 or \u201040 mV are virtually identical, and they are similar to the currents from multichannel patches held at \u201040 mV. 4. The voltage\u2010dependent, time\u2010variant kinetics of individual L\u2010type Ca2+ channels are unaltered if the patch is removed from the cell and forms an inside\u2010out configuration. In these experiments the internal membrane was bathed with an artificial, intracellular\u2010like solution containing no phosphorylating enzymes or substrates. 5. Cells bathed in 20 mM\u2010Ba2+ solutions and held at \u201080 mV have currents with an early phase that inactivates in tens of milliseconds, a late phase that inactivates in hundreds of milliseconds, and a large, slow tail current. Currents from \u201040 mV have only the late phase and practically no tails. However, if the maximum current is less than 0.1 pA pF\u20101, records from either \u201080 or \u201040 mV are virtually identical, and they are similar to currents from cells with higher channel density held at \u201040 mV. Furthermore, if cells are stimulated before full recovery from inactivation, the reduced current is accompanied by slower inactivation. 6. Whole\u2010cell currents in 1.5 mM\u2010Ca2+ solutions are entirely abolished by addition of 20 microM\u2010nifedipine, and they are enhanced 2\u20103 times by addition of 30 microM\u2010cyclic AMP and 3 mM\u2010ATP to the whole\u2010cell recording electrode. The whole\u2010cell currents in 20 mM\u2010Ba2+ solutions are also completely blocked by 20 microM\u2010nifedipine, regardless of kinetics or holding potential. Thus, by definition, the cells we are studying contain only L\u2010type channels.(ABSTRACT TRUNCATED AT 400 WORDS)<\/jats:p>","DOI":"10.1113\/jphysiol.1991.sp018835","type":"journal-article","created":{"date-parts":[[2014,12,17]],"date-time":"2014-12-17T17:15:31Z","timestamp":1418836531000},"page":"307-334","source":"Crossref","is-referenced-by-count":32,"title":["Gating of L\u2010type Ca2+ channels in embryonic chick ventricle cells: dependence on voltage, current and channel density."],"prefix":"10.1113","volume":"443","author":[{"given":"M","family":"Mazzanti","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"L J","family":"DeFelice","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Y M","family":"Liu","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[1991,11]]},"container-title":["The Journal of Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1113%2Fjphysiol.1991.sp018835","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/jphysiol.1991.sp018835","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,23]],"date-time":"2023-10-23T04:55:57Z","timestamp":1698036957000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/jphysiol.1991.sp018835"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1991,11]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1991,11]]}},"alternative-id":["10.1113\/jphysiol.1991.sp018835"],"URL":"https:\/\/doi.org\/10.1113\/jphysiol.1991.sp018835","archive":["Portico"],"relation":{},"ISSN":["0022-3751","1469-7793"],"issn-type":[{"value":"0022-3751","type":"print"},{"value":"1469-7793","type":"electronic"}],"subject":[],"published":{"date-parts":[[1991,11]]}}}