Nitrous oxide-induced c-Fos expression in the rat brain.

Induction of c-Fos has previously been used to map locations of cells in the central nervous system (CNS) that are activated by ethanol administration. Only a few studies examining a restricted range of CNS areas have identified brain areas activated by nitrous oxide (N(2)O). Because ethanol and N(2)O have overlapping physiological, psychological and behavioral effects, we hypothesized that these drugs act on similar sites in the CNS.

Conditioned place aversion and self-administration of nitrous oxide in rats.

The rewarding/aversive effects of nitrous oxide (N(2)O) were evaluated using the place conditioning paradigm. Male Long-Evans rats (N=103) received a daily 40-min gas exposure for 8 consecutive days that alternated between two distinct chambers. A control group received placebo gas in both chamber types, while the N(2)O groups (8%, 15%, 30%, and 60% N(2)O) received four consistent pairings of N(2)O with one chamber type and four pairings of placebo gas with the other.