INVOLVEMENT OF NITRIC-OXIDE IN LONG-TERM POTENTIATION IN THE DENTATE GYRUS INVIVO

Effects of NO synthase inhibitors on long-term potentiation (LTP) were investigated in the dentate gyrus of anesthetized rats. Administration of N(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) or N(G)-methyl-L-arginine (50 nmol) also showed similar effects. The LTP-blocking effect of L-NAME was reversed by coadministration of L-arginine (500 nmol). These results suggest that NO participates in the generation of LTP at the dentate gyrus in vivo.