Summary
A behavioural test involving potentiation of the effects of an acute injection of β-phenylethylamine (10 mg kg−1 i.p.) was used to assess the time-course of type-B MAO inhibition after administration of (−)deprenyl (5 mg kg−1 i.p.) and of MD 240928 (20 mg kg−1 i.p.) respectively. Potentiation of the effects of β-phenylethylamine was observed 1 h after injection of (−)deprenyl or MD 240928. This effect was still evident 120 h after administration of (−)deprenyl but not 24 h after administration of MD 240928. Comparisons of ex vivo estimates of MAO activity yielded a corresponding time-course for the recovery of this enzyme. The extent of MAO inhibition required for potentiation of the effects of β-phenylethylamine was inferred from a comparison of the behavioural test results and the ex vivo MAO activity observed after (−)deprenyl administration. These comparisons indicate a significant underestimation of MD 240928-induced MAO inhibition using ex vivo measures. This underestimation is interpreted as evidence fordilution effects in the ex vivo assay of MAO inhibition. The potentiation of effects of β-phenylethylamine under the present conditions is proposed as a useful and simple test for effects of reversible type-B MAO inhibitors.
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Turkish, S., Yu, P.H. & Greenshaw, A.J. Monoamine oxidase-B inhibition: a comparison of in vivo and ex vivo measures of reversible effects. J. Neural Transmission 74, 141–148 (1988). https://doi.org/10.1007/BF01244780
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DOI: https://doi.org/10.1007/BF01244780