Effects of a nitric oxide donor on behavior and interaction with nitrous oxide in the mouse light/dark exploration test.

There is controversy whether endogenous nitric oxide (NO) is involved in anxiogenesis or anxiolysis. This study was conducted to determine the influence of the NO donor, 3-morpholinosyndnonimine (SIN-1), on resting and nitrous oxide (N(2)O)-induced behaviors in the mouse light/dark exploration test. I.c.v. doses of 0.3 and 1.0 microg SIN-1 both increased the time spent in the light compartment. When pretreated with 0.1 microg SIN-1, mice responded to N(2)O with an apparent additive increase in the time spent in the light compartment. These findings further support a functional role of NO in regulation of anxiety and mediation of N(2)O-induced behavior.