Correlation of increased grooming behavior and motor activity with alterations in nigrostriatal and mesolimbic catecholamines after alpha-melanotropin and neuropeptide glutamine-isoleucine injection in the rat ventral tegmental area.

摘要: 1. We wished to further study the behavioral effects of alpha-melanotropin (alpha-MSH), melanin-concentrating hormone (MCH), and neuropeptide glutamine-isoleucine (NEI). 2. To this effect we administered alpha-MSH, MCH, NEI in ventral tegmental area rat, a structure where these neuropeptides are highly concentrated. elucidate biochemical mechanisms neuropeptides, determined degree grooming behavior levels catecholamines. after administration. 3. preselected those animals responding central injection alpha-MSH with excessive behavior. at dose 1 microg/0.5 microL, each side area, bilaterally. studied behavior, locomotor activity, total scores, 30 65 min administration peptides. 4. Three groups were decapitated immediately or injection. measured dopamine (DA), noradrenaline (NA), dopac/dopamine ratio (DOPAC/DA) determine steady state catecholamines an indirect measure DA release metabolism, respectively. 5. Injections produced significant elevations both peptide This was correlated decreases content, increases DOPAC DOPAC/DA ratio. In caudate putamen, changes occurred nucleus accumbens, present Conversely, there no alterations NA either putamen any time 6. resulted increased caudatus but not accumbens. concentrations caudatus. 7. MCH did produce accumbens 8. Our results indicate (a) There is correlation as induced for injected here, extrapyramidal (b) between (c) changed (d) Absence catecholamines, particular correlates absence area. 9. conclusion, exogenous peptide-specific, probably associated catecholamine metabolism Both seem stimulate nigrostriatal system. While appears mesolimbic system well, may exert its actions through DA, The precise contribution NA, relative role behaviors remain be elucidated.