Effect of the cerebral tryptaminergic system on the turnover of dopamine in the striatum of the rat.
The effect of the cerebral 5-hydroxytryptamine system on the turnover of striatal 3,4-dihydroxyphenyl-ethylamine (dopamine) was investigated by measuring the level of dopamine and one of its metabolites in rats depleted of cerebral 5-hydroxytryptamine or treated with a 5-hydroxytryptamine receptor blocker. Treatment with p-chlorophenylalanine induced, in addition to a reduction in striatal 5-hydroxytryptamine and 5-hydroxyindol-3-ylacetic acid, an increase in the striatal concentration of dopamine, a diminution in the concentration of homovanillic acid in the same cerebral area, and a reduction in the rise of this acid after the administration of a butyrophenone derivative or tetrabenazine. Treatment with methysergide also reduced the increase of homovanillic acid induced by the butyrophenone. When probenecid was given to rats treated with p-chlorophenylalanine, homovanillic acid failed to accumulate, whereas the accumulation of 5-hydroxyindol-3-ylacetic acid was unaffected. The decay of dopamine after alpha-methyl-p-tyrosine administration was normal for the first 6 h but was later reduced in rats given p-chlorophenylalanine or methysergide. The results suggest that the lack of activation of 5-hydroxytryptamine receptors leads to a reduction in the turnover of dopamine in the nigrostriatal pathway.
Fuenmayor
L D
LD
Bermúdez
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M
D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D010134:Fenclonine / Q000494:pharmacology; D006719:Homovanillic Acid / Q000378:metabolism; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D008297:Male; D011339:Probenecid / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*
D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D006916:5-Hydroxytryptophan; D011339:Probenecid; D010134:Fenclonine; D004298:Dopamine; D006719:Homovanillic Acid