| Abstract: | The effects of L-aspartic acid (L-ASP) on spontaneous and evoked activity in afferent nerve fibers were investigated by perfusing the basal membrane of sea skate electroreceptors (the ampullae of Lorenzini) with this substance. It was found that perfusion with physiological saline containing L-ASP exerted a primarily excitatory effect on afferent activity (threshold concentration: 10–7 M). When synaptic transmission was blocked by magnesium ions, activity was restored in the afferent fibers if L-ASP was added to the solution and spike activity persisted for longer; this would imply the presence of desensitizing processes in the postsynaptic receptors of the ampullae. Finding would lead to the conclusion that L-ASP and L-glutamate fulfill a set of criteria for likely neurotransmitters in the ampullae of Lorenzini.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 19, No. 1, pp. 61–67, January–February, 1987. |
