Involvement of nitric oxide in long-term potentiation in the dentate gyrus in vivo

Effects of NO synthase inhibitors on long-term potentiation (LTP) were investigated in the dentate gyrus of anesthetized rats. Administration ofN^G-nitro-L-arginine methyl ester (L-NAME; 50 nmol i.c.v.) greatly blocked the generation of LTP without affecting basal responses.N^G-nitro-L-arginine (50 nmol) orN^G-methyl-L-arginine (50 nmol) also showed similar effects. The LTP-blocking effect of L-NAME was reversed by coadministration ofL-arginine (500 nmol). These results suggest that NO participates in the generation of LTP at the dentate gyrus in vivo.