Abstract
In the previous paper (1) it has been reported that the intracarotid injection of 0.1 mg/kg of reserpine in rabbit increased the content of noradrenaline in the whole brain and brain stem at 30 minutes, and also in the brain stem at one hour after the administration, while the content of noradrenaline in the atria and of adrenaline in the adrenal gland did not change, or decreased below 10% of the normal content. But, thereafter, the content of noradrenaline in brain tissues and the atria, and of adrenaline in the adrenal gland decreased steeply and the peak effect was attained at the third hour of the administration. The animal behaved normally or sometimes showed a slight sign of motor excitement (2). The intravenous injection of 0.1 or 1.0 mg/kg of reserpine decreased the content of central and peripheral noradrenaline and adrenaline. The decrease of the peripheral noradrenaline or adrenaline caused by the intracarotid injection of 1.0 mg/kg of reserpine was usually more marked than the decrease of the amine caused by the intravenous injection of same dose of reserpine. From the results, Higuchi (1) suggested that the depletion of catecholamine in the peripheral organs by, reserpine was derived from two mechanisms: the biochemical effect and the central effect. The central effect of reserpine to decrease the content of noradrenaline or adrenaline in the peripheral organs might be caused by the decrease of noradrenaline in the sympathetic center` located in the brain stem.
Shimamoto and Torii (2) showed that the previous treatment of rabbit with cocaine or methamphetamine reversed the reserpine sedation at an early period of reserpine administration, but, later potentiated the reserpine sedation. Kikuchi (3) obtained the similar effect of the pretreatment of cocaine or methamphetamine on the action of reserpine in the rabbit from the elect roe ncephalographic studies.
In the present report, the effect of pretreatment of rabbit with methamphetamine or cocaine on the catecholamine depleting action of reserpine was studied.
