Abstract
By use of the brain microdialysis technique we show that administration of gamma(1)-melanocyte stimulating hormone (gamma(1)-MSH) into the ventral tegmental area of anaesthetized rats causes an increase in the release of extracellular dopamine and its metabolite 3,4-dihydroxyphenylacetic acid in the nucleus accumbens, while gamma(2)-MSH causes the opposite effect. Moreover, gamma(2)-MSH pre-treatment considerably reduced the gamma(1)-MSH-induced effects. Our findings suggest an opposing action of two gamma-MSH-activated pathways on the mesolimbic dopaminergic system, which could be important in the maintenance of a balanced psychoactivation state.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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3,4-Dihydroxyphenylacetic Acid / metabolism
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Animals
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Brain Chemistry / drug effects
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Brain Chemistry / physiology
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Dopamine / metabolism*
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Limbic System / drug effects*
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Limbic System / metabolism
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Male
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Neural Pathways / drug effects*
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Neural Pathways / metabolism
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Neurons / drug effects
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Neurons / metabolism
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Nucleus Accumbens / drug effects*
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Nucleus Accumbens / metabolism
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Rats
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Rats, Sprague-Dawley
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Up-Regulation / drug effects
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Up-Regulation / physiology
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Ventral Tegmental Area / drug effects*
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Ventral Tegmental Area / metabolism
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gamma-MSH / metabolism
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gamma-MSH / pharmacology*
Substances
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gamma-MSH
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3,4-Dihydroxyphenylacetic Acid
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Dopamine