7-NI More Effectively Reduces the Inhibitory Effects of Hydrogen Peroxide on Synaptic Transmission in Crayfish Compared to L-NAME

Abstract

Both oxidative stress and increased nitric oxide (NO) production have been linked to the progression of various neurological disorders. However, the specific pathogenesis of these disorders is unknown. To investigate the role of nitric oxide in cell death, we researched the effect of selective and non-selective nitric oxide synthase (NOS) inhibitors on synaptic transmission in crayfish during exposure to the oxygen derivative H2O2, which mimics oxidative stress. We hypothesized that n-Nitroarginine methyl ester (L-NAME), a nonselective NOS inhibitor, will be more effective than 7Nitroindazole (7-NI), a selective nNOS inhibitor, at preventing the negative effects of H₂O₂ on the excitatory junction potential (EJP) in crayfish. We performed intracellular recording to measure the change in synaptic transmission before and after the addition of H₂O₂. Our results did not support our hypothesis, as 7-NI more effectively mitigated the inhibitory effects of H₂O₂ on synaptic transmission than L-NAME. We conclude that the ineffectiveness of L-NAME may be a result of the drug targeting NOS isoforms necessary for synaptic transmission.