The effect of subcutaneous injections of benzedrine sulphate on the activity of white rats.

Abstract

The revolving drug activity of 15 white rats was measured over a period of 60 days, during the last 40 of which each rat was injected every 4th day with a 3 mg./kg. dose of benzedrine sulfate. Control injs. of salt soln. were also made and the hourly activity of the rats on these days compared with activity on days of drug. For the 4-hr, period following inj. the rats were approx. 7 times as active on drug as on salt days, reaching a level higher than at any other time. The increased activity due to benzedrine was followed by a decrease during the remainder of the 24 hr. period so that the total activity level was found to be equivalent to that of control days. For 10 injs. of drug over the exptl. period of 40 days no tolerance was reliably indicated.