An examination of the force-interval relationship in chronic diabetic rat papillary muscle.

The purpose of the present study was to fully characterize the force-interval relationship of the right ventricular papillary muscle from chronic diabetic rats, and, to more closely examine the alterations in the beta phase reported previously. The condition of chronic diabetes resulted in several alterations in the force-interval relationship, primarily in the beta phase of force development. Alterations in the percent contribution of beta to the total amplitude and the rate and time constants of the beta phase were identified and suggest alterations in the capacity of the diabetic tissue to transport calcium through the exchange compartment of the sarcolemma to the sarcoplasmic reticulum release compartment. Reduction of the transmembrane Na$\sp+$ gradient by 40% resulted in an improvement in force development of the chronic diabetic suggesting a limitation of the chronic diabetic tissue to allow calcium influx through Na$\sp+$/Ca$\sp{2+}$ exchange during rest. A decrease in extracellular calcium during rest resulted in a reduction in force development in the diabetic. (Abstract shortened by UMI.)Dept. of Kinesiology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1990 .M382. Source: Masters Abstracts International, Volume: 30-03, page: 0656. Thesis (M.H.K.)--University of Windsor (Canada), 1990