Amiloride Inhibits Synaptic Transmission at Crayfish Neuromuscular Junctions, but no Evidence Suggests Its Interaction with DRNFLRFamide

Abstract

FMRFamide-activated sodium channels (FaNaCs) are similar to mammalian acid-sensing ion channels (ASICs). We analyzed the reaction of FaNaCs exposed to DRNFLRFamide (DF2) at the crayfish neuromuscular junction. We measured excitatory postsynaptic potentials (EPSPs) after exposing crayfish extensor muscle cells first to DF2, then DF2 and amiloride, and finally, amiloride alone. Contrary to previous studies, DF2 inhibited synaptic transmission. Amiloride also inhibited synaptic transmission. Therefore, FaNaCs are similar to ASICs in regard to their response to amiloride. The results were inclusive in determining the interaction between amiloride and DF2.