SOME PHARMACOLOGIC ACTIONS OF LYCORAMINE

In anesthetized cats, an intravenous injection of lycoramine at 3—5 mg/kg produced a transient fall of systemic blood pressure, potentiated the hypotensive response elicited by acetylcholine or by the electrical stimulation of the peripheral end of vagus, and increased the activity of smooth muscle in the intestines. This drug also enhanced the blocking action of suceinylcholine on the myoneural junction. Under the same experimental conditions, galanthamine in doses of 0.25—2mg/kg produced similar effects. When the solution of lycoramine was applied Iocally to the rabbit's eye, it caused pupillary constriction and abolished the mydriatic action of atropine. In vitro, lycoramine increased the reactivity of guinea-pig ileum and frog's rectus abdominis muscle to acetylcholine. In cats intravenous or intra-arterial (through lingual artery) injections of lycoramine or galanthamino produced no marked influence on the contractions of nictitating membranes elicited by electrical stimulation of preganglionic fibers, but theypotentiated the action of acetylcholine injected through lingual artery. In EEG recordings of normal rabbits lyooramine (15—20mg/kg) or galanthamine(3—5mg/kg)induced the arousal response and this action could be antagonized by some anticholinergic drugs such as atropine, scopolamine or benactyzine.