Chronic Ethanol Exposure Decreases Synaptic Transmission at the Crayfish Neuromuscular Junction and Creates Tolerance to Acute Ethanol Exposure

Abstract

Previous research has shown that ethanol acts as a depressant at chemical synapses, decreasing the amplitude of excitatory postsynaptic potentials (EPSPs). We investigated the effects of 0.5% ethanol on the crayfish neuromuscular junction (NMJ) under two conditions: acute and chronic. Two groups of crayfish, one chronically exposed to ethanol and the other previously unexposed, were tested under normal and acute ethanol conditions. Standard intracellular recording was used to measure EPSP amplitudes. Our findings demonstrate that both acute and chronic ethanol exposure decrease EPSP amplitudes and that crayfish neuromuscular junctions develop an ethanol tolerance, a decrease in drug responsiveness with repeated chronic exposure.