Effects of L-741,741, a selective dopamine receptor antagonist, on anxiety tested in the elevated plus-maze in mice

Dopamine systems are involved in modulation of anxiety. Although the action of D-1/5, D-2 and D-3 receptor antagonists on anxiety has been documented in different animal models, little is known about the influence of D-4 dopamine antagonists. The aim of this study was to examine the effects of L-741,741 (0.75, 1.5 and 3 mg/kg i.p.), a selective D-4 dopamine receptor antagonist, on anxiety tested in the elevated plus-maze. Forty-eight albino adult male mice of the OF. 1 strain were used. Animals were randomly allocated to one control group receiving physiological saline and dymethyl-sulphoxide (DMSO) (10%) and three experimental groups receiving L-741,741 injections. Tests were performed 30 min after injections for a duration of 5 min. A number of classical parameters were collected: i) open arm duration; ii) closed arm duration; iii) central platform duration; iv) open arm frequency; v) closed arm frequency; vi) central platform frequency; and vii) number of rearings. L-741,741 did not produce any significant behavioral changes under present test conditions, suggesting that the dopamine D-4 receptor might not be involved in the modulation of anxiety-related behaviors in the plus-maze. (C) 2003 Prous Science. All rights reserved.