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Publications (2)5.37 Total impact

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    ABSTRACT: We have previously shown that acute administration of the 5-HT1C/5-HT2 receptor agonist, 1-(2,5-dimethoxy-4-iodophenyl)2-aminopropane (DOI), elevates brain tryptophan levels. The present work aimed to investigate the mechanisms responsible for this elevation. Acute s.c. administration of a 2-mg/kg dose of DOI increased brain tryptophan levels but did not affect either plasma free tryptophan, plasma total tryptophan, brain 5-HT, or brain 5-hydroxyindoleacetic acid. Pretreatment with the 5-HT1C/5-HT2 receptor antagonist, LY 53857, prevented the DOI-induced increase in brain tryptophan levels, whilst the increase was reduced by the 5-HT2 receptor/alpha 1-adrenoceptor antagonist, ketanserin, and to a lesser extent, by the ganglionic blocker, chlorisondamine. On the other hand, pretreatment with either the peripherally acting 5-HT1C/5-HT2 receptor blocker, BW 501C67, the 5-HT uptake enhancer, tianeptine, the 5-HT uptake blocker, paroxetine, or the beta 2-adrenoceptor antagonist, ICI 118.551, proved ineffective. Lastly, pretreatment with LY 53857 did not affect the immobilization-induced elevation in brain tryptophan levels. It is concluded that the elevation in brain tryptophan levels induced by DOI but not that induced by stress is due to central 5-HT1C and 5-HT2 receptor stimulation.
    European Journal of Pharmacology 02/1993; 231(1):77-82. · 2.68 Impact Factor
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    ABSTRACT: Earlier studies have indicated that the sympathoadrenal system and the corticotropic axis control brain levels of tryptophan (Trp), the precursor of 5-hydroxytryptamine (5-HT). We investigated the effects of 5-HT receptor agonists known to activate the sympathoadrenal system and/or the corticotropic axis on plasma and brain Trp levels. Neither the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, 0.5 mg/kg s.c.), nor the 5-HT1C receptor agonist 1-(3-chlorophenyl)piperazine (mCPP, 2.5 mg/kg s.c.) affected plasma and brain Trp levels. The 5-HT2 receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)2-aminopropane (DOI, 0.5-2 mg/kg s.c.) increased brain Trp levels, an effect which was significant for the two highest doses used (1.5-2 mg/kg s.c.).
    European Journal of Pharmacology 05/1992; 214(1):101-3. · 2.68 Impact Factor