Role of NO-ergic system of the he nucleus accumbens in metabolic disturbances under acute stress

The aim of the study was to evaluate the involvement of nitricergic system within the shell part of the nucleus accumbens (NAc) by injection of L-arginine, a nitric oxide precursor, and L NAME, a nitric oxide synthase inhibitor in the metabolic disturbances induced by acute stress in the male rat. Male Wistar rats were cannulated unilaterally in the left part of the shell of the NAc. Correspondingly, five minutes before each stress session (60 seconds of foot electrical shock of 40 mA), the animals either received sterile saline (0.25 μl/rat) or different doses of L-arginine and/or L-NAME (1, 5, and 10 μg/rat) for four days. Blood samples were taken on day 1 and 4 for plasma cortisol measurements. In addition, animals’ food and water intake, time elapsing for food intake were recorded. Finally, their adrenal glands were removed and weighted. The level of cortisol significantly increased in the positive control after the fourth day. The L-arginine (1 μg/Rat) decreased the level of cortisol, water and food intake. In opposite, the L-NAME (1 μg/Rat) increased the cortisol level of plasma and metabolic function. Both L-arginine and L-NAME (10 μg/Rat) significantly decreased the level of cortisol but increased the amount of water and food intake. The L-arginine (1 μg/Rat) increased the weight of adrenal gland in both the presence of absent of stress conditions. There was an interaction between the drugs and stress on the time for initiation of food intake. Our data indicated that nitric oxide within the left side of shell part of NAc may have a role in the metabolic disturbances induced by stress.