1. Substitution by different anions for chloride in physiological salt solutions leads to binding between Ca2+ and the anion. Experiments designed to test effects of Cl- therefore often show mixed effects of changes in Cl- and Ca2+ activity. 2. This mixed effect is demonstrated in neurons of the snail, Helix pomatia: current-voltage characteristics and membrane potential are described during reduction of extracellular Cl- using different anions as substitutes. Methylsulphate is concluded to be the best substitute in this preparation. 3. The association constants for the binding of Ca2+ to a number of anions is given.
Comparative Biochemistry and Physiology - Part A: Comparative Physiology, 1975, Vol 52, Issue 2, p. 317-322