On the Stimulant Effect of Benzedrine Sulphate

Abstract

Benzedrine sulphate has been reported as having a stimulant effect in certain types of patients with mental and physical fatigue and exhaustion. It has been found of value in arousing patients with narcolepsy, 1-3 chronic exhaustion,^4-6 and simple depression, 5 occasionally of value in depressed types of psychoneuroses 5 , 7 but of little use in catatonic dementia praecox. 7 , 8 Blackburn 9 believes that it raises the intelligence quotient in these patients. Experiments herein reported revealed that benzedrine sulphate does not stimulate spinal reflexes or skeletal muscle directly and that it is not depressant toward respiration as is epinephrine. This evidence supports the view that the stimulant action of benzedrine is entirely cerebral.

The time required for hind limb flexion after stimulating the pad of the foot with dilute (1-5000 to 1-1000) sulphuric acid in 20 brain-only pithed frogs was increased an average of 172% and in 85% of animals following the injection into the dorsal lymph sac of 0.05 mg. of benzedrine sulphate in 0.5 cc. of distilled water. The same dose of epinephrine hydrochloride or meta-synephrine hydrochloride had no consistent effect on the reflex time which on the average was slightly increased. Mean changes in the reflex time are shown in Fig. 1. In larger doses epinephrine also depressed the spinal reflex, an effect previously known but not generally recognized. 10 In relatively large doses benzedrine is thus even more depressant than epinephrine on the spinal reflexes of frogs.

The application of 0.001% benzedrine sulphate to the excised gastrocnemius muscle of 17 frogs produced a weaker and shorter contraction when the muscle was stimulated by a galvanic current.

A decrease in the height of contraction occurred in 94% of experiments, the average decrease was 39% and the standard deviation of the average decrease was 18%.