BEHAVIORAL-RESPONSE TO SKF-38393 AND QUINPIROLE FOLLOWING CHRONIC ANTIDEPRESSANT TREATMENT

The effects of chronic administration of antidepressant drugs (21-22 d ays s.c. via osmotic mini-pumps) on the behavioural responses of male Sprague-Dawley rats to (-)-quinpirole hydrochloride (0.05 mg kg(-1) s. c., 5 min) and (+/-)-SKF 38393 hydrochloride (10 mg kg(-1) s.c., 5 min ) were investigated. Desipramine hydrochloride (10 mg kg(-1) per day), phenelzine sulphate (10 mg kg(-1) per day) and clorgyline hydrochlori de (1 mg kg(-1) per day) attenuated the suppression of locomotor activ ity induced by quinpirole, a dopamine D-2-like receptor agonist, while clomipramine hydrochloride (10 mg kg(-1) per day) was without effect. Yawning elicited by quinpirole was absent in phenelzine- and clorgyli ne-treated rats, but unaffected in rats treated chronically with desip ramine and clomipramine. SKF 38393, a dopamine D-2-like receptor agoni st, significantly increased locomotor activity and time spent grooming in control animals. There were no significant effects of antidepressa nts on the behavioural responses to SKF 38393.