title: Unexpected potentiation by discriminant benzamide derivatives of stereotyped behaviours elicited by dopamine agonists in mice.
abstract: Among four stereotyped manifestations that can be simultaneously quantified in mice treated with apomorphine (APO), two of them (climbing and sniffing) emerge at low APO dosages (below 1 mg/kg) whereas licking and sniffing require APO dosages above 6 mg/kg. However, in mice pretreated (either i.p. or i.c.v.) with sulpiride (especially the levo isomer) or (+/-)amisulpride in moderate dosage stereotyped licking and sniffing are elicited by APO in much lower dosage (0.75 mg/kg). As a consequence, in mice pretreated with these benzamide derivatives and receiving 0.75 mg/kg APO, a biphasic effect was observed: licking and gnawing progressively appear at low dosages, whereas they are progressively abolished at higher dosages. This potentiation of the effects of APO by (+/-) amisulpride is even more obvious (maximal scores increased) with larger test-doses of the dopamine agonist (up to 5 mg/kg). Amisulpride also allows the emergence of the two stereotyped behaviours in mice receiving other dopamine agonists in subthreshold dosages (Dipropyl 5,6-ADTN, dexamphetamine or cocaine). The potentiation of APO is still observed after dopamine depletion by reserpine and alpha-methylparatyrosine, whereas that of dexamphetamine is abolished. In contrast with the benzamide derivatives, haloperidol does not potentiate at any dosage the effect of APO but, at 0.15 mg/kg, suppresses licking and gnawing elicited by 0.75 mg/kg APO in mice pretreated with 6.25 mg/kg amisulpride or veralipride.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001549:Benzamides / Q000494:pharmacology*; D004298:Dopamine / Q000502:physiology*; D018492:Dopamine Antagonists; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D006801:Humans; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D011954:Receptors, Dopamine / Q000187:drug effects*; D013239:Stereotyped Behavior / Q000187:drug effects*
chemical_list: D001549:Benzamides; D018492:Dopamine Antagonists; D011954:Receptors, Dopamine; D001058:Apomorphine; D004298:Dopamine