Nitric oxide synthase inhibition and food intake: effects on motivation to eat and in female mice.

Recent studies have demonstrated that nitric oxide may play an important role in the regulation of food intake. The studies reported here extend these findings by demonstrating that NG-nitro-arginine-methylester, N-Arg(ME), a nitric oxide synthase inhibitor, decreased intake of a highly palatable substance (i.e., milk), though at a higher dose than necessary for decreasing consumption of food pellets. N-Arg(ME) failed to inhibit lever press for milk reward in nonprefed mice, but decreased lever pressing in prefed mice. N-Arg(ME) decreased food intake in female mice, being most potent in proestrus. These studies suggest that nitric oxide synthase inhibition decreases food intake without inducing aversion or illness.