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 synthase (nNOS) inhibitor 7-nitroindazole on the long-term potentiation (LTP) induced by l-clausenamide (Cla) in rat hippocampus in vivo.


METHODS
Population spike (PS) of evoked potentials was determined by extracellular recording technique in the hippocampal dentate gyrus (DG) of anesthetized rats.


RESULTS
7-Nitroindazole 2 nmol icv blocked the induction of LTP elicited by high-frequency (100 Hz) stimulation or Cla 5 nmol icv (P < 0.01), and L-arginine 225 mg.kg-1 i.p. prevented the action of 7-nitroindazole (P < 0.01).


CONCLUSION
Nitric oxide produced by nNOS plays a role in the induction of Cla-induced LTP in hippocampus.