Effects of some depressant drugs on synaptic responses to glutamate at the crayfish neuromuscular junction.

Excitatory junction currents produced by glutamate were recorded with an extracellular electrode at the neuromuscular junction of the crayfish. Pentobarbitone, phenobarbitone, diazepam, chlordiazepoxide and procaine had only minimal effects on current decay at concentrations which are highly effective in other preparations. The glutamate synapse in the crayfish appears relatively resistant to these drugs. In contrast, ether and halothane increased the rate of decay of the currents at concentrations which are comparable to those occurring during anaesthesia.