ABSTRACT
The study was performed on three groups of male rats of Wistar strain at the age of three month: group I (n = 10), the control group, group II (n - 10), consisting in animals treated by 0,3 mg of metthylene blue i. m. /100 g body weight / day for 9 days (a guanylyl-cyclose inhibitor), and group III (n - 10), includes animals treated by ga vage by 30 mg L-arginine /1 OOg body weight / day(the precursor for NO). Open-field spontaneous motility and emotivity and aquisition of the active avoidance conditioned reflexes in the shittle-box were tested.  L-arginine significantly increased the leaming ability, emotivity and spontanous motility, and methylene blue induced leaming disabilities. This study indirectly demonsrated the important role of L-arginine-NO system, in LTP.

Keywords: leaming, long term potetiation, L-arginine, NO.