Summary
The behavioural syndrome caused by l-5-HTP in rats was used for the study of effects of selective 5-HT uptake inhibitors and inhibitors of MAO on central 5-HT receptors. A good correlation was found between the relative potencies of drugs in inhibiting the 5-HT uptake in the rat brain and in intensifying l-5-HTP-induced behavioural stimulation. The potentiation of the l-5-HTP syndrome by the MAO inhibitors correlated with the inhibition of the A- but not of the B-form of the brain monoamine oxidase.
In rats treated with the maximally inhibiting dose of a 5-HT uptake inhibitor, MAO inhibitors were still able to increase the intensity of the l-5-HTP syndrome, while the combination of maximal doses of two 5-HT uptake inhibitors did not produce a more intense syndrome than that produced by one 5-HT uptake inhibitor alone.
The l-5-HTP-induced behavioural syndrome in rats seems to afford an experimental model allowing the quantification and characterization of the interaction of drugs with serotonin metabolism in the brain.
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Ortmann, R., Waldmeier, P.C., Radeke, E. et al. The effects of 5-HT uptake- and MAO-inhibitors on l-5-HTP-induced excitation in rats. Naunyn-Schmiedeberg's Arch. Pharmacol. 311, 185–192 (1980). https://doi.org/10.1007/BF00510258
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DOI: https://doi.org/10.1007/BF00510258