Dorsal striatal mechanisms involved in the dopamine D2 receptor-mediated potentiation of apomorphine-induced jaw movements.
The role of dorsal striatal mechanisms in the regulation of apomorphine-induced jaw movements was studied. Jaw movements induced by apomorphine (0.2 mg/kg i.v.) were potentiated by quinpirole (10 micrograms/0.2 microliter) injected into the dorsal part of the striatum 10 min before apomorphine. Quinpirole injection into the ventral part of the striatum did not affect the effects of apomorphine. the quinpirole-induced potentiation in the dorsal striatum was prevented by l-sulpiride (25 ng), nemonapride (1 microgram), SCH23390 (1 microgram) or methylscopolamine (1 microgram), but not muscimol (50 ng), co-administered with quinpirole. Injection of these drugs alone 10 min before apomorphine failed to alter the effects of apomorphine. l-Sulpiride (25 ng) injected into the dorsal striatum 60 min before apomorphine increased the frequency of jaw movements induced by apomorphine (0.2 mg/kg). The l-sulpiride-induced potentiation was prevented by methylscopolamine (0.1 microgram) or l-sulpiride (25 ng) injected into the dorsal striatum 10 min before apomorphine; we had already found that this potentiation was also blocked by SCH23390. It is suggested that a synergistic dopamine D1/D2 receptor interaction underlies both the quick-onset potentiation by quinpirole and the delayed-onset potentiation by l-sulpiride.
Kikuchi de Beltrán
K
K
Department of Pharmacology, Nihon University School of Dentistry, Tokyo, Japan.
Koshikawa
N
N
Miwa
Y
Y
Kobayashi
M
M
D000818:Animals; D001058:Apomorphine / Q000008:administration & dosage / Q000494:pharmacology*; D001549:Benzamides / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D015259:Dopamine Agents / Q000008:administration & dosage / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D004357:Drug Synergism; D004873:Ergolines / Q000008:administration & dosage / Q000494:pharmacology; D007568:Jaw / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D019832:N-Methylscopolamine; D010276:Parasympatholytics / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D019257:Quinpirole; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D012602:Scopolamine Derivatives / Q000494:pharmacology; D013469:Sulpiride / Q000494:pharmacology
D001549:Benzamides; D001552:Benzazepines; D015259:Dopamine Agents; D065127:Dopamine D2 Receptor Antagonists; D004873:Ergolines; D010276:Parasympatholytics; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; D012602:Scopolamine Derivatives; D019257:Quinpirole; D013469:Sulpiride; D001058:Apomorphine; C030265:nemonapride; D019832:N-Methylscopolamine