Calcium in Ciliary and Muscular Movement

Abstract

IT is interesting to note that the unbalance obtained by reducing the calcium content of physiological solutions can to some extent be offset by the addition of small quantities of lipoids to the solution. Thus frog heart rendered hypodynamic, or even arrested, by Ringer solution less varying amounts of calcium chloride, can be made to beat normally again by adding small quantities of sodium oleate, of sodium palmitate, of impure lecithin, or of ox blood thrombin to the Ringer, the pH being maintained unaltered the effect was not observed with very pure lecithin or very pure kephalin, but a similar effect was obtained with lyso-lecithin, which first reduces the beat and also contracts the heart. Similarly, Clark and others¹ have shown that frog heart rendered hypodynamic by prolonged beating in Ringer solution shows increased activity when given extra calcium, sodium oleate, impure but not pure lecithin, impure but not pure kephalin, or serum. Ox blood thrombin, serum, and all but the purest samples of phospholipins contain traces of soaps which may well account for the activity of these substances in offsetting calcium deficiency. Mytilus cilia will beat for some time in artificial sea water at pH 6·5, but are quickly arrested if they are put in a similar medium at the same pH without calcium (removed as chloride)² the ciliary beat is restored in such a calcium-free solution at the same pH if traces of one of the following substances are added: sodium dodecyl sulphate (the magnesium present rendered the oleate and palmitate of sodium insoluble and therefore ineffective), hexa-decyl-trimethyl-ammonium bromide, lyso-lecithin, impure lecithin, or ox blood thrombin. Triolein, sodium butyrate and sodium glycerophosphate showed no restorative effect. In considering these facts, it should be noted that calcium is found to be more active under lipoid than under protein monolayers.