{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,4]],"date-time":"2025-11-04T22:28:04Z","timestamp":1762295284974},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"3","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1977,12,15]]},"abstract":"<jats:p>The kinetics of uptake of Ca2+ by rat heart mitochondria were studied by a spectrophotometric method with Arsenazo III indicator. The exponential rate coefficients measured with or without added phosphate increase with the amount of Ca2+ added up to about 24\u03bcm. Evidence is given that the effect is attributable to a combination of formation of chelates at low concentrations to act as Ca2+ buffers, with co-transport of substrate to provide more respiratory fuel. The inhibitory effect of Mg2+ depends on the Ca2+ concentration, so with a constant [Mg2+] the low concentrations of Ca2+ are most inhibited, and the rate coefficients are still more Ca2+-dependent. Ca2+ uptake is slowed by local anaesthetics such as butacaine and dibucaine, and also by propranolol and palmitoyl-CoA. After an uptake, the release of Ca2+ was investigated. The spontaneous release involves an initially slow and small appearance of free Ca2+ and is followed by an auto-accelerated phase. The release is accompanied by a gradual decrease in internal ATP; it is initiated by palmitoyl-CoA (reversed by carnitine), by lysophosphatidylcholine, by Na+ salts (reversed by oligomycin) and by K+ salts added to a K+-free medium containing valinomycin. The process is probably a response to an increased energy load imposed on the mitochondria by the various conditions, which include the spontaneous action of phospholipase activated by traces of Ca2+. The problem of how much mitochondrial activity is participating in normal heart Ca2+ turnover is discussed, and experiments showing only 7\u201314% exchange of the mitochondrial Ca2+ occurring in vivo in 10 or 20min are reported.<\/jats:p>","DOI":"10.1042\/bj1680447","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T20:09:18Z","timestamp":1439237358000},"page":"447-456","update-policy":"http:\/\/dx.doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":48,"title":["The uptake and release of calcium by heart mitochondria"],"prefix":"10.1042","volume":"168","author":[{"given":"Eric J.","family":"Harris","sequence":"first","affiliation":[{"name":"Department of Biophysics, University College London, London WC1E 6BT, 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\/168\/3\/447\/569964\/bj1680447.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/168\/3\/447\/569964\/bj1680447.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,26]],"date-time":"2021-11-26T14:18:13Z","timestamp":1637936293000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/168\/3\/447\/6074\/The-uptake-and-release-of-calcium-by-heart"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1977,12,15]]},"references-count":0,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1977,12,15]]}},"URL":"https:\/\/doi.org\/10.1042\/bj1680447","relation":{},"ISSN":["0264-6021"],"issn-type":[{"value":"0264-6021","type":"print"}],"subject":[],"published":{"date-parts":[[1977,12,15]]}}}