Involvement of nitric oxide in nitrous oxide anxiolysis in the elevated plus-maze.
We recently reported that inhibition of nitric oxide (NO) production by the NO synthase (NOS) inhibitor L-NG-nitro arginine (L-NOARG) antagonized the behavioral effects of a benzodiazepine (BZ) in a mouse paradigm for screening anxiolytic drug activity. Because other research has found that the anesthetic gas nitrous oxide (N2O) also produces BZ-like behavioral effects, the present research was conducted to ascertain whether NO might also be involved in N2O anxiolysis. Male Swiss-Webster mice were tested in an elevated plus-maze inside an inflatable glovebag. Exposure to N2O significantly increased exploratory activity on the open arms of the plus-maze, as measured by the number of entries into the open arms and the time spent on the open arms. Pretreatment with L-NOARG significantly reduced the N2O-induced elevation in open arm activity. This antagonism of the N2O effect was reversed by ICV treatment of L-NOARG-pretreated mice with L-arginine but not D-arginine. These findings indicate that NO possibly mediates behavioral effects of N2O in an animal model for anxiety.
Caton
P W
PW
Department of Psychology, Rockford College, IL 61108.
Tousman
S A
SA
Quock
R M
RM
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors; D000818:Animals; D014151:Anti-Anxiety Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001007:Anxiety / Q000139:chemically induced* / Q000503:physiopathology; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects; D005106:Exploratory Behavior / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D019001:Nitric Oxide Synthase; D019335:Nitroarginine; D009609:Nitrous Oxide / Q000008:administration & dosage / Q000494:pharmacology*
D014151:Anti-Anxiety Agents; D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D009609:Nitrous Oxide