Bombesin increases dopamine function in rat brain areas |
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Authors: | Erik Widerlöv Robert A Mueller Gerald D Frye George R Breese |
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Institution: | 1. Psychiatric Research Center, University of Uppsala, Ulleråker Hospital, S-750 17 Uppsala, Sweden;2. Department of Anesthesiology, University of North Carolina, School of Medicine, Chapel Hill, NC 27514, USA;3. Department of Psychiatry and Pharmacology, Biological Sciences Research Center University of North Carolina, School of Medicine, Chapel Hill, NC 27514, USA |
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Abstract: | 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. |
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Keywords: | Bombesin Central nervous system Dopamine High performance liquid chromatography (HPLC) Interaction Metabolites Neuropeptides Serotonin |
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