Modulation by intracellular Ca++ of GABA activated Cl- extrusion from Deiters' neuron.

The increase in 36Cl- in --> out permeation across plasma membranes from the Deiters' neurons by GABA on the cytoplasmic side is modulated by Ca++. The GABA stimulation was maximal with Ca++ on the intracellular side at the physiologically likely concentration of 3 x 10(-8) M. A lower effect was found in the 10(-7) - 10(-5) M [Ca++]i range with a total disappearance of it at [Ca++] of .2 mM. This Cl- extrusion mechanism is likely to be involved in the establishment of a Cl- out --> in electrochemical gradient. Modulation of it by intracellular Ca++ transients may be of physiological importance.