{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,2]],"date-time":"2025-11-02T07:04:45Z","timestamp":1762067085507},"reference-count":0,"publisher":"Rockefeller University Press","issue":"4","content-domain":{"domain":["rupress.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1976,4,1]]},"abstract":"<jats:p>Values for ionized [Ca] in squid axons were obtained by measuring the light emission from a 0.1-mul drop of aequorin confined to a plastic dialysis tube of 140-mum diameter located axially. Ionized Ca had a mean value of 20 x 10(-9) M as judged by the subsequent introduction of CaEGTA\/EGTA buffer (ratio ca. 0.1) into the axoplasm, and light measurement on a second aequorin drop. Ionized Ca in axoplasma was also measured by introducing arsenazo dye into an axon by injection and measuring the Ca complex of such a dye by multichannel spectrophotometry. Values so obtained were ca. 50 x 10(-9) M as calibrated against CaEGTA\/EGTA buffer mixtures. Wth a freshly isolated axon in 10 mM Ca seawater, the aequorin glow invariably increased with time; a seawater [Ca] of 2-3 mM allowed a steady state with respect to [Ca]. Replacement of Na+ in seawater with choline led to a large increase in light emission from aequorin. Li seawater partially reversed this change and the reintroduction of Na+ brought light levels back to their initial value. Stimulation at 60\/s for 2-5 min produced an increase in aequorin glow about 0.1% of that represented by the known Ca influx, suggesting operationally the presence of substantial Ca buffering. Treatment of an axon with CN produced a very large increase in aequorin glow and in Ca arsenazo formation only if the external seawater contained Ca.<\/jats:p>","DOI":"10.1085\/jgp.67.4.433","type":"journal-article","created":{"date-parts":[[2004,5,13]],"date-time":"2004-05-13T22:45:45Z","timestamp":1084488345000},"page":"433-467","update-policy":"http:\/\/dx.doi.org\/10.1085\/jgp.crossmarkpolicy","source":"Crossref","is-referenced-by-count":239,"title":["Ionized calcium concentrations in squid axons."],"prefix":"10.1085","volume":"67","author":[{"given":"R","family":"Dipolo","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J","family":"Requena","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"suffix":"Jr","given":"F J","family":"Brinley","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"L J","family":"Mullins","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A","family":"Scarpa","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"T","family":"Tiffert","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"291","published-online":{"date-parts":[[1976,4,1]]},"container-title":["The Journal of general physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/rupress.org\/jgp\/article-pdf\/67\/4\/433\/1810657\/433.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/rupress.org\/jgp\/article-pdf\/67\/4\/433\/1810657\/433.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,7,27]],"date-time":"2023-07-27T11:35:11Z","timestamp":1690457711000},"score":1,"resource":{"primary":{"URL":"https:\/\/rupress.org\/jgp\/article\/67\/4\/433\/57856\/Ionized-calcium-concentrations-in-squid-axons"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1976,4,1]]},"references-count":0,"journal-issue":{"issue":"4","published-print":{"date-parts":[[1976,4,1]]}},"URL":"https:\/\/doi.org\/10.1085\/jgp.67.4.433","relation":{},"ISSN":["0022-1295","1540-7748"],"issn-type":[{"value":"0022-1295","type":"print"},{"value":"1540-7748","type":"electronic"}],"subject":[],"published":{"date-parts":[[1976,4,1]]}}}