Inhibiting Endogenous Hydrogen Sulfide Production Decreases Amplitudes of EPSPs at the Crayfish Neuromuscular Junction

Abstract

H₂S has been shown to have an effect at the neuromuscular junction. The enzymes CBS and CSE both produce H₂S, but at the neuromuscular junction CBS is mainly responsible for its production. We determined that H₂S alters synaptic transmission at the crayfish neuromuscular junction by decreasing the amplitude of EPSPs. This was accomplished by inhibiting the enzyme CBS and comparing inhibited EPSPs to baseline EPSPs. In order to inhibit the enzyme we used hydroxylamine. In addition to inhibiting CBS, hydroxylamine is known to create nitric oxide (NO). This variable was eliminated by the application of Carboxy-PTIO, a NO chelator. These data show that H₂S acts as neuromodulator at the crayfish neuromuscular junction, however it might have different effects in crayfish than in mammals.