Bombesin increases dopamine function in rat brain areas.
Bombesin is a tetradecapeptide heterogenously distributed in the mammalian brain. Bombesin (45 micrograms) given intracisternally (IC) to unanesthetized rats increased the accumulation of dihydroxyphenylalanine (DOPA) in striatum, olfactory tubercles and hypothalamus after DOPA-decarboxylase inhibition, thus indicating an increased dopamine synthesis. A dose-dependent increase in dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), the principal dopamine metabolites, was seen in several brain areas 1 hr after IC injection of bombesin (0-60 micrograms). In striatum and olfactory tubercles HVA increased more than DOPAC with a maximal increase after 30-45 micrograms. In a time-course experiment a biphasic change of dopamine metabolites was observed in the olfactory tubercles with an actual decrease in metabolite levels 4 hr after 60 micrograms IC bombesin injection. Co-administration of bombesin and naloxone (8 mg/kg IP) or ethanol (2.25 g/kg IP) did not affect the increase in dopamine metabolites seen after bombesin alone. The action of IC administered bombesin on dopamine function was most pronounced in hypothalamus indicating a neuroendocrine regulatory of the peptide.
D000818:Animals; D001839:Bombesin / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism; D007700:Kinetics; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009830:Olfactory Bulb / Q000378:metabolism; D009928:Organ Specificity; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism
D010455:Peptides; D012701:Serotonin; D009270:Naloxone; D004295:Dihydroxyphenylalanine; D001839:Bombesin; D004298:Dopamine