Effect of X537A on the release of amino acids in retina

Abstract

Summary The effect of the Ca2+ ionophore X537A on the release of neurotransmitters in the chick retina has been studied. X537A induces the release of three postulated neurotransmitters (taurine, glycine and γ-aminobutyrate) and does not affect the release of leucine. The X537A induced release of the neurotransmitters is accompanied by an enhancement in the uptake of 45Ca2+. As the net amount of Ca2+ in retina is not modified by X537A, it is probable that the release of neurotransmitters results from an enhancement in the turnover of Ca2+ across the membrane. The relative quantitative release of the three neurotransmitters is modified by the presence of Na+.