Endocannabinoids Inhibit EPSPs at the Crayfish Neuromuscular Junction

Abstract

Previous research has shown that cannabinoid (CB) receptors are present at the pre-synaptic nerve terminals in crayfish neuromuscular junctions and that endocannabinoids alter the release of neurotransmitters in humans and other animals. Our research was directed towards finding physiological evidence of endocannabinoids at the crayfish neuromuscular junction. We hypothesized that by applying an exogenous cannabinoid to the crayfish neuromuscular junction, the excitatory post-synaptic potentials (EPSPs) would decrease. To test this, we first measured a control group of EPSP amplitudes with a crayfish exposed to normal saline solution; we then emptied the dissection dish and refilled it with a diluted solution of arachidonylcyclopropylamide (ACPA), a synthetic cannabinoid. By measuring the subsequent EPSP amplitudes and comparing the results to that of the control group, we discovered that endocannabinoids do indeed have a function at the crayfish neuromuscular junction.