Abstract
Using the mechanoelectric transducer, the relaxation of the oyster heart muscle after the stimulation of anodal current pulse has been studied. The inhibition of spontaneous rhythmic contraction is greatly influenced by the phase of the cardiac cycle where the stimulation is applied. On the other hand, the relaxation of tension below the spontaneous diastolic tension is independent of the phase of the cardiac cycle and is dependent on the level of diastolic tension such as cardiac tone. The grade of anodal relaxation is dependent on the intensity of stimulation. The relaxation can be produced either by a steady current flow or by repetitious pulses, suggesting mechanisms different from the relaxation of mytilus adductor muscle. The grade and the rate of anodal relaxation are greater when the muscle is in the tonic state, than when it is in the relaxed state. These findings are not influenced by an application of a procain solution, thus suggesting the independency of this relaxation from neural inhibition.
The research reported in this document has been made possible through the suppor and sponsorship of the U. S. Department of Army through its Far East Research Office.
