EVIDENCE FOR A MECHANISM OF SODIUM-INDUCED CALCIUM RELEASE IN FROG AURICULAR TRABECLES

Abstract

In a Ca-free, Mg-free medium containing EGTA [ethyleneglycol bis[.beta.-aminoethyl ether] N,N''-tetraacetic acid] (10-3 M) auricular trabecles develop a slow inward current which is a pure Na current. After 12 min in this medium, it is still possible to obtain a phasic mechanical activity which shows a perfect correlation with the current. A mechanism of Na-induced Ca release apparently is present at the level of some internal sites.