The Effects of the Endocannabinoid Agonists, AM356 and ACPA, on the Crayfish Neuromuscular Junction

Abstract

Endocannabinoids are retrograde transmitters, which inhibit the release of neurotransmitters. We hypothesized that endocannabinoids would operate similarly in crayfish neuromuscular junctions as they do at other synapses, lowering the amplitude of the excitatory post-synaptic potentials (EPSPs). We tested this by exposing the superficial extensor muscles in the crayfish tail to two synthetic CB1 agonists, arachidonylcyclopropylamide (ACPA) and methanandamide (AM356). We found that ACPA decreased the EPSPs as expected. AM356, however, did not; in fact when exposed to AM356 the EPSP amplitudes increased.