THE ACTIVITY OF THE PACEMAKER PREVIOUS TO THE DISCHARGE OF A MUSCULAR IMPULSE

Abstract

Spontaneous conducted responses of visceral smooth muscles are initiated by a local, graded activity indicated by a rise in negativity and an increase in tonus. If one lead is placed on the pacemaker of the ureter, the other at some distance, each response is preceded by a weak local potential which may be either a single phase of slowly rising negativity or regular, gradually increasing, oscillations. Impulses arise from the negative crests of the oscillations. The local potentials are accompanied by weak tonus changes. Evidence is presented that the rhythmic slow potential waves of the intestine and uterus are responsible for the initiation of conducted impulses and determine the rhythmicity of the muscles.