CENTRAL AND AUTONOMIC EFFECTS FOLLOWING THE COMBINED ADMINISTRATION OF SODIUM ARSENITE AND 2,3-DIMERCAPTOPROPANOL (BAL)

¹ Department of Pharmacology and Materia Medica, Georgetown University, School of Medicine

Rabbits receiving BAL intramuscularly and subsequently sodium arsenite by vein, develop an "explosive" reaction characterized by crying, motor excitement, constriction of the pupils, profuse salivation and lip sweating, lacrimation, bradycardia, injection of the conjunctiva, reddening of the lids and uvea. These reactions may also be elicited if arsenite is given first and BAL later. These effects, particularly the central excitement, may also be elicited under pentobarbital narcosis.

These effects are opposed or counteracted by atropine only if they are referable to parasympathetic stimulation. Thus, the bradycardia, salivation, sweating, and lacrimation are prevented by atropine but, curiously, the pupillary constriction is not.

Cats and dogs do not develop pupillary constriction as a result of the combined administration of BAL and arsenite, but may show involuntary micturition and defecation.

These phenomena are of relatively short duration and none of the animals observed died as a result of the combined administration of the two agents. Compounds of BAL and arsenite prepared in vitro do not produce the characteristic biological effects.

Arsenates, arsphenamines and mercurials do not elicit the characteristic central and peripheral effects following the administration of BAL.

Possible mechanisms by which the "explosive" reaction may be brought about are discussed.