Cholecystokinin octapeptide and caerulein injection into the dorsomedial nucleus accumbens potentiate apomorphine-induced jaw movements in rats.
The effects of bilateral intra-accumbal and intrastriatal injections of CCK-8 sulphate and its analogue, caerulein, on apomorphine-induced jaw movements were studied in ketamine-anaesthetized rats after C1 spinal transection. Jaw movements were detected by a photo-transducer attached to the mandible. CCK-8 (5, 10 and 20 ng) and its analogue, caerulein (1 and 5 ng), injected into the dorsomedial nucleus accumbens increased the frequency of apomorphine (0.2 mg/kg i.v.)-induced jaw movements. The potentiation was prevented by administration of a CCK-A receptor antagonist, lorglumide (5 ng), together with CCK-8 (20 ng) or caerulein (5 ng). Injection of lorglumide alone into the dorsomedial nucleus accumbens did not alter apomorphine (0.5 mg/kg i.v.)-induced jaw movements. Injections of CCK-8 (20 ng) and caerulein (5 ng) into adjacent sites (the ventrolateral nucleus accumbens, dorsal striatum and ventral striatum) did not affect the responses elicited by apomorphine (0.2 mg/kg i.v.). These results demonstrate that CCK-8 modulates responses elicited by a dopamine receptor agonist, apomorphine, in a region of the brain where CCK-8 is known to co-exist with dopamine.
Koshikawa
N
N
Department of Pharmacology, Nihon University School of Dentistry, Tokyo, Japan.
Kikuchi de Beltrán
K
K
Saigusa
T
T
Kobayashi
M
M
Stephenson
J D
JD
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D002108:Ceruletide / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology; D004357:Drug Synergism; D007568:Jaw / Q000187:drug effects* / Q000502:physiology; D008297:Male; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012844:Sincalide / Q000494:pharmacology*
D002108:Ceruletide; D012844:Sincalide; D001058:Apomorphine