Characteristics of the dopamine receptors involved in the anorectic effects of apomorphine in mice.
In food-deprived mice apomorphine injected SC induced a brief (15-30 min) dose-dependent (30-150 micrograms/kg) reduction in food intake. This effect occurred in naive mice as well as in mice habituated to a food deprivation procedure. The anorectic effect of apomorphine (150 micrograms/kg SC) was antagonized by sulpiride (ID50 = 8.6 mg/kg) and by haloperidol (ID50 = 66 micrograms/kg) but domperidone was ineffective (250 micrograms/kg). Mice submitted to a semi-chronic (6 d) blockade of dopamine receptors by haloperidol or injected intracerebroventricularly with 125 micrograms 6-hydroxydopamine 21 d before testing failed to develop a hypersensitivity to the anorectic effect of apomorphine (60 micrograms/kg). Although a single apomorphine injection (5 mg/kg) induced tolerance to the hypothermic effect of a second apomorphine injection of 150 micrograms/kg, it did not modify the anorectic effect. Repeated apomorphine injection (5 x 5 mg/kg) resulted in a slight but significant reduction in apomorphine-induced anorexia. A similarly significant reduction was not observed in mice submitted to repeated injections of dexamphetamine (5 x 5 mg/kg).
Duterte-Boucher
D
D
Unité de Neuropsychopharmacologie expérimentale, UA 1170 du CNRS, UFR de Médecine & Pharmacie de Rouen, Saint-Etienne-du-Rouvray, France.
Naudin
B
B
Costentin
J
J
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001067:Appetite Depressants; D001831:Body Temperature / Q000187:drug effects; D003913:Dextroamphetamine / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology; D018492:Dopamine Antagonists; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D006220:Haloperidol / Q000494:pharmacology; D006892:Hydroxydopamines; D008297:Male; D051379:Mice; D016627:Oxidopamine; D011954:Receptors, Dopamine / Q000187:drug effects*; D013563:Sympathectomy, Chemical; D009435:Synaptic Transmission / Q000187:drug effects
D001067:Appetite Depressants; D018492:Dopamine Antagonists; D006892:Hydroxydopamines; D011954:Receptors, Dopamine; D016627:Oxidopamine; D006220:Haloperidol; D001058:Apomorphine; D003913:Dextroamphetamine; D004298:Dopamine