The Force of Contraction of the Rabbit Papillary Muscle Preparation as a Function of the Frequency and Pattern of Stimulation

SUMMARY The relationship between peak tension developed during a twitch in isolated rabbit papillary muscle and the frequency and pattern of stimulation has been examined. The muscle was subjected to a short train of stimuli followed by n single α‐stimulus; this pattern of stimuli was repeated at regular intervals. The experimental variables were the frequency and number of stimuli in the train, the time interval after the end of the train and the α‐stimulus, and the rest period between each stimulus pattern. The peak tension of the response to the α‐stimulus as a function of these four variables was determined in a number of ways and a tentative mathematical model is formulated which describes this aspect of the results. The response to the stimuli of the train is considered in relationship to the model and the form of model which could describe these and other results is discussed.