Stimulation of D1 and D2 dopamine receptors produces additive anorectic effects.
In food-deprived mice the D1 dopamine agonist SKF 38393 induced dose dependent anorexia (ED50 = 2.6 mg/kg). This effect was reversed by the D1 antagonist SCH 23390. In similar conditions, the D2 dopamine agonist RU 24926 also induced dose dependent anorexia (ED50 = 0.19 mg/kg). This effect was reversed by the D2 antagonist (+/-) sulpiride. The mixed D1/D2 agonist apomorphine also induced an anorectic effect (150 micrograms/kg sc) which was completely reversed by (+/-) sulpiride (25 mg/kg, ip) but unaffected by SCH 23390 (5-30 micrograms/kg). The dose response curve obtained by associating SKF 38393 (2.5 mg/kg) with increasing doses of RU 24926 was roughly parallel to that obtained with RU 24926 alone. This indicates that effects of two drugs were additive. Although both D1 and D2 receptors regulate food consumption, the anorectic effect of apomorphine appears to involve only D2 receptors.
Ladurelle
N
N
CNRS URA 1170 UFR de Médecine et Pharmacie de Rouen, Saint-Etienne-du-Rouvray, France.
Duterte-Boucher
D
D
Costentin
J
J
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D000855:Anorexia / Q000139:chemically induced*; D001058:Apomorphine / Q000494:pharmacology*; D015259:Dopamine Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005247:Feeding Behavior / Q000187:drug effects; D008297:Male; D051379:Mice; D010627:Phenethylamines / Q000494:pharmacology; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology*; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D013469:Sulpiride / Q000494:pharmacology
D015259:Dopamine Agents; D010627:Phenethylamines; D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; C025254:RU 24926; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D013469:Sulpiride; D001058:Apomorphine