ACTION OF FORMALIN AND HISTAMINE ON TENSION AND POTENTIAL CURVES OF A STRIATED MUSCLE, THE RETRACTOR PENIS OF THE TURTLE

Abstract

The retractor penis of the turtle treated with formaldehyde gives a veratrin-like mechanical response, the action potential lasting throughout the contraction and having a similar form to that of the tension curve. Histamine shortens both mechanical and electrical responses. Formalin appears to affect the initial peak of the action potential and the later potential accompanying tension development differentially, thus suggesting a distinction between a conducted nerve-like process and a resultant process of mechanical response. If the first process only were all-or-none, the local effects of electrical stimulation at the cathode might be explained as the sum of the effects of the irritable process and of the shock itself upon the contractile mechanism.