Effect of tabernanthine on the turnover time of brain catecholamines in normal and hypobaric hypoxic rats

The central effects of tabernanthine on noradrenaline and dopamine turnover times were studied in the hypothalamus, the striatum and the remainder of the brain of normal and hypobaric hypoxic rats, the latter state corresponding to 5,200m (410mm Hg) and 7,000m (320mm Hg). Catecholamine cerebral level were not modified by the drug in either instance. At normal atmospheric pressure the catecholamine turnover times were slightly decreased by tabernanthine. Hypobaric hypoxia alone increased noradrenaline and dopamine turnover times by inhibiting oxygen-dependent enzymes. Tabernanthine antagonized the effect of hypobaric hypoxia especially in dopaminergic areas. Antagonism was complete at 5,200m but only partial at 7,000m. This phenomenon may be related to the stimulatory properties of the drug.