ANXIOLYTIC ACTIVITY OF TACHYKININ NK2, RECEPTOR ANTAGONISTS IN THE MOUSE LIGHT-DARK BOX

The tachykinin NK2 receptor antagonists, GR100679 (0.02-200 mu g/kg s. c.) and (+/-)-SR48968 (0.05-5.0 mu g/kg s.c.), dose-dependently increa sed the time which mice spent in the light side of the light-dark box. There was no evidence of sedation or other overt behaviours. The ampl itudes of these effects were similar to that evoked by diazepam (1.75 mg/kg s.c.). These results indicate a disinhibitory action of NK2 anta gonists on suppressed behaviours in a novel aversive environment. This suggests an involvement of NK2 receptors in anxiety-related behaviour s.