휜쥐에서 Toloxatone과 Iproniazid의 Monoamine Oxidase 억제작용에 관한연구 : Tyramine의 고혈압유발작용에 미치는 영향

Effect of Toloxatone on the Pressor Effect of Tyramine in Rat: Comparison with Monoamine Oxidase Inhibition by Iproniazid

The objectives of the present experiments were to characterize the activity of toloxatone, a short-acting reversible MAO-inhibitor, related to the “cheese effect” by intestinal tyramine in comparison to that of iproniazid, a long acting irreversible MAO-inhibitor. Tyramine was administered orally to the male rats(Sprague-Douley, 250-350g, BW ) to measure the systolic blood pressure. Tyramine alone administered orally increased the blood pressure. Toloxatone 20 and 30mg.kg injected subcutaneously enhanced the pressor effect of tyramine. The enhancement of toloxatone on the tyramine-effect subsided in 50-60 minutes. Iproniazid 20 and 30 mg/kg injected subcutaneously enhanced the pressor effect of tyramine. The enhancement of iproniazid on the tyramine- effect persisted for more than 120 minutes. The enhancements on tyramine-effect of toloxatone and iproniazid were of exactly the same pattern and degree for initial 40-50 minutes regardless the dose administered. These data suggest that tyramine itself can elevate the blood pressure of rat toloxatone has the same characteristics of the pharmacological action in the intestinal mucosa as that of iproniazid, and the difference of enhancement of the pressor effect of tyramine between toloxatone and iproniazid may be determined by the half lives in the body.