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THE EFFECT OF FASTING ON THE METABOLISM OF 5-HYDROXYTRYPTAMINE AND DOPAMINE IN THE BRAIN OF THE MOUSE

Authors

  • L. D. Fuenmayor

    1. Agricultural Research Council Institute of Animal Physiology, Babraham, Cambridge CB2 4AT, England
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    • 1

      Cátedra de Farmacología, Escuela de Medicina José Vargas, Universidad Central de Venezuela, Apartado de Correos No. 76359, Caracas 107, Venezuela.


Abstract

Abstract— The turnover of 5-hydroxytryptamine in the forebrain and of dopamine in the striatum was studied in mice fasted for 20 h. Such mice showed an increased tissue concentration of 5-hydroxyindoleacetic acid in the forebrain and an increased accumulation of this acid after probenecid. Fasted mice also showed a higher concentration of homovanillic acid in the striatum than fed mice. However, the administration of probenecid produced a smaller increase in homovanillic acid concentration in fasted than in fed mice. The decay of dopamine following α-methyl-p-tyrosine was reduced in fasted mice at 2 h, but not at 1 h or 6 h after administration of the inhibitor. The possibility that fasting increases the activity of some dopaminergic neurones while decreasing the activity of others is considered. The existence of a pool of homovanillic acid at a site within the striatum where the probenecid-sensitive transport is not effective is postulated.

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