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Investigation of mechanisms of synaptic transmission in ampullae of Lorenzini in the skate

Abstract

The effect of magnesium ions, L-glutamate (L-GLU), and the diethyl ester of glutamic acid (DEE-GLU) on temperature and electrical sensitivity of the ampullae of Lorenzini in skates was studied by the method of perfusion of the basal membrane of electroreceptor cells and recording spike activity from single nerve fibers. Addition of 10−4–10−5 M L-GLU to the solution was shown to cause an increase in the spontaneous discharge frequency of receptors with low initial level of activity (8–20 spikes/sec) and a decrease in receptors with spontaneous activity of 22–42 spikes/sec. In solution with an increased magnesium ion concentration (15–50 mM) both spontaneous and evoked receptor activity was blocked, Under these conditions the addition of L-GLU to the solution caused partial recovery of spontaneous receptor activity. Reversible blocking of spontaneous and evoked receptor activity was observed in a solution containing 10−4–10−3 M DEE-GLU. It is suggested that L-GLU is the synaptic transmitter in the ampullae of Lorenzini of the skate.

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Additional information

I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 13, No. 3, pp. 292–298, May–June, 1981.

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Akoev, G.N., Andrianov, Y.N. & Vol'pe, N.O. Investigation of mechanisms of synaptic transmission in ampullae of Lorenzini in the skate. Neurophysiology 13, 213–219 (1981). https://doi.org/10.1007/BF01065112

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Keywords

  • Glutamic Acid
  • Nerve Fiber
  • Synaptic Transmission
  • Spontaneous Activity
  • Spike Activity