EFFECTS OF ATROPINE AND RELATED ALKALOIDS ON EPINEPHRINE INDUCED CONTRACTIONS OF THE CAT NICTITATING MEMBRANE

¹ Department of Pharmacology and Department of Ophthalmology, University of California, San Francisco, California

The effects of atropine, methylatropine, scopolamine and methylscopolamine on the response of the chronically denervated and acutely decentralized nictitating membrane of the cat to epinephrine were studied.

The results show that 1 or 8 mg/kg of atropine decreased the response of the acutely decentralized and chronically denervated membrane to epinephrine. The other three alkaloids caused a slight decrease in the response of time chronically denervated membrane to epinephrine, and an increase in the response of time acutely decentralized membrane to epinephrine.

Inasmuch as atropine, in the dose traditionally given to abolish muscarinic effects (1 mg/kg), causes a decrease in the response to epinephrine in both the chronically denervated and acutely decentralized membranes, perhaps another compound should be used as an antimuscarinic agent. These experiments show that of the alkaloids studied, an equivalent dose of methylscopolamine seems to be best suited to replace atropine.