Epinephrine stimulation slightly increased distensibility but did not change the rate of stress relaxation in isolated cat hearts, suggesting its action is confined to contractile elements.
Does epinephrine stimulation alter stress relaxation and distensibility in isolated cat hearts?
The rapid diastolic relaxation observed with epinephrine stimulation relates to the dynamics of the contraction process rather than to lowered myocardial viscosity.
To investigate the cause of the rapid relaxation observed in the epinephrine-stimulated heart, stress relaxation and distensibility have been measured in the isolated perfused cat heart and in isolated papillary muscles. During epinephrine stimulation, distensibility was slightly increased but there was no change in the rate of stress relaxation. This would suggest that the action of epinephrine is confined to the contractile elements without any direct effect on the viscoelastic elements responsible for stress relaxation. The rapid diastolic relaxation observed in these hearts therefore relates to the dynamics of the contraction process rather than to lowered myocardial viscosity.
Leach et al. (Mon,) reported a other. Epinephrine was evaluated on Stress relaxation and distensibility. Epinephrine stimulation slightly increased distensibility but did not change the rate of stress relaxation in isolated cat hearts, suggesting its action is confined to contractile elements.
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