Effects of 7-nitroindazole on long-term potentiation induced by l-clausenamide and high-frequency stimulation in rat hippocampus in vivo

AIM: To study the antagonistic effect of selective neuronal nitric-oxide sy nthase (nNOS) inhibitor 7-nitroindazole on the long-term potentiation (LTP) induced by l-clausenamide (Cla) in rat hippocampus in vivo. METHODS: Popul ation spike (PS) of evoked potentials was determined by extracellular recor ding technique in the hippocampal dentate gyrus (DG) of anesthetized rats. RESULTS: 7-Nitroindazole 2 nmol icy blocked the induction of LTP elicited b y high-frequency (100 Hz) stimulation or Cla 5 nmol icv (P < 0.01), and L-a rginine 225 mg.kg(-1) ip prevented the action of 7-nitroindazole (P < 0.01) . CONCLUSION: Nitric oxide produced by nNOS plays a role in the induction o f Cla-induced LTP in hippocampus.