Effect of beta-Adrenergic Blockers on Experimentally-induced Convulsion and Narcosis

ABSTRACT

Effects of beta-adrenergic blockers and related agents were investigated on experimental convulsions of chicks induced with strychnine, pentylenetetrazol or electroshock and on thiopental sleeping time of rabbits. Convulsions of chicks due to strychnine were significantly inhibited by all beta-adrenergic blockers except dichloroisopreterenol. Propranolol inhibited electroshock convulsion as well, but none of the blockers inhibited pentylenetetrazol convulsion. Furthermore, the mortality of chicks due to large dose of pentylenetetrazol was greatly increased by treatment of beta-adrenergic blockers. Pindolol alone showed diazepam-like anticonvulsive effect against low doses of pentylenetetrazol. Pretreatment with beta-adrenergic blockers caused a marked increase in thiopental sleeping time in rabbits. Prolongation of thiopental sleep due to propranolol was abolished by premedication of animals with reserpine or tranylcypromine. Thiopental sleeping time was prolonged by Zizyphus extract, though less effective than beta-adrenergic blockers. It is felt that the anticonvulsive or sleep enhancing effect of beta-adrenergic blocking agents has an intimate relationship with endogenous adrenergic amines and the receptors.