Influence of cholecystokinin on central monoaminergic pathways.
Dopamine (DA) and cholecystokinin octapeptide carboxy-terminal (CCK-8) have been found to coexist in some mesolimbic neurons. The present investigation was undertaken in order to study the biochemical and behavioral interactions between CCK-8 and some central monoaminergic pathways. The action of the sulfated form of CCK-8 (10 micrograms/10 microliter intracerebroventricularly) on DA turnover in nucleus accumbens, olfactory tubercles and corpus striatum of the rat was determined after DA synthesis inhibition with alpha-methyl-p-tyrosine (250 mg/kg i.p.). Also, CCK-8 action (1-30 micrograms intracisternally) on DA synthesis was assessed by measuring accumulation of dihydroxyphenylalanine (DOPA) after DOPA-decarboxylase inhibition with NSD-1015 (m-hydroxybenzylhydrazine, 100 mg/kg i.p.). The contents of DA and its main metabolites, dihydroxyphenylacetic acid and homovanillic acid, together with serotonin and its main metabolite, 5-hydroxyindoleacetic acid (5-HIAA), were measured in different brain areas after direct injection of CCK-8 into the ventral tegmental area (A10) or nucleus accumbens. Further, the effect of CCK-8 on amphetamine-induced locomotion and apomorphine-induced stereotypies was studied along with changes in spontaneous locomotion and rearing after CCK-8 injection into the ventral tegmental area and nucleus accumbens. No consistent statistically significant effects of CCK-8 on biochemical or behavioral assessments on measures of DA function were observed. However, injection of high doses of CCK-8 into the ventral tegmental area significantly decreased levels of 5-HIAA in the nucleus accumbens, olfactory tubercles and striatum.
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry / Q000187:drug effects; D002766:Cholecystokinin / Q000008:administration & dosage / Q000494:pharmacology*; D004295:Dihydroxyphenylalanine / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D006834:Hydrazines / Q000494:pharmacology; D007276:Injections, Intraventricular; D008124:Locomotion / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012844:Sincalide
D006834:Hydrazines; D010446:Peptide Fragments; D004295:Dihydroxyphenylalanine; D002766:Cholecystokinin; C004297:3-hydroxybenzylhydrazine; D000661:Amphetamine; D012844:Sincalide; D004298:Dopamine