Characterization of enkephalin release from rat striatum.

Using antisera specific for methionine- and leucine-enkephalin, we studied the characteristics of the release of these peptides from rat striatal slices. Only 2-3% of the total tissue stores of enkephalin could be released by potassium-depolarization; similar percentages were released from globus pallidus, thalamus, and nucleus accumbens. Enkephalin release from hippocampus could not be detected. The striatal release of both enkephalins was affected similarly by changes in potassium and calcium levels in the superfusion medium. Lithium has no effect on either basal or potassium-stimulated release; tyr-arg did not affect basal release of either peptide. Striatal enkephalin levels were stable during the short-term incubation periods used in these experiments.