[Effects of aspartic acid in the electroreceptors of the skate].

To identify the afferent transmitter in ampullary electroreceptors of the marine skates effects of L-aspartic acid (L-ASP) were examined using bath application of the drug. Perfusion of the basal membrane with L-ASP produced an increase in activity in most experiments (threshold concentrations 10(-7) M). L-GLU and L-ASP were identical in their ability to activate the afferents. In the presence of presynaptic blockade (high Mg2+) bath application of L-ASP restored the resting activity, suggesting a postsynaptic action of L-ASP. The results are consistent with the view that L-GLU, L-ASP or a related compound may play a role in afferent transmission in the ampullae of Lorenzini of skates.