INHIBITION OF SWEATING BY SALTS OF HYOSCINE AND HYOSCYAMINE.

In tests of the inhibitory effect on sweating of optical isomers of hyoscyamine camphor sulfonate in one man, the levorotatory isomer was about 70 times more active than the dextrorotatory isomer. There was no significant difference in effect of equimolar doses of the levorotatory isomer and of atropine sulfate. Weight loss, body temperature, and heart rate were recorded for several hours on eight resting men at 41 and 52C. At 41C, seven men received intravenous injections of atropine sulfate and scopolamine hydrobromide, four men received atropine methylnitrate and the remaining four men received methscopolamine bromide. The doses were equimolar for the active base. The quaternary salts atropine methylnitrate and methscopolamine bromide were between two and three times more potent than the tertiary salts atropine sulfate and scopolam amine hydrobromide. The hyoscyamine salts were indistinguishable from the hyoscine salts with respect to inhibition of sweating and elevation of heart rate and skin and rectal temperatures. Because the salts differ widely in their potency in the central nervous system, the similarity of their peripheral actions supports the view that the action of low doses of atropine on temperature regulation is mainly peripheral. Author