Measurement of heat production in skeletal muscle with HgCdTe infrared detector.

点击翻译按钮获取中文摘要

Measurements of heat production during contraction have been performed by use of a thermopile to obtain information about the mechanism of chemomechanical conversion in muscle contraction. In the thermopile experiment, there is some assumption that all the local region of muscle respond mechanically and thermally in the same manner. It is possible to obtain information about heat produced along the long axis of muscle during muscle contracion by the thermopile, but not possible to do that in the local region of muscle. It is unknown (1) whether time course of heat production in the local region of tetanized muscle is same as that in the whole region. (2) how thermal distribution on the muscle surface in the resting muscle is shown, and how it changes immediately after isometric tetanus. (3) how local heat produced during isometric tetanus relates to mechanical response of the same region.We constracted heat measurement apparatus by use of HgCdTe infrared detector and used a thermography to investigate above questions. Frog sartorius muscle (Rana catesbeiana) was mounted to the holder at in situ length with several metal fine markers and isometrically tetanized for 2-5 sec. Time course of heat production in central local region of muscle was same as that in whole region of muscle measured by the thermopile with 3 heat rate components. Thermal distributions in the resting and tetanized muscle were non-uniform along the entire length of muscle. In general, the local regions near pelvic end and central part tended to shorten by stretching those near the tibial end, and the amount of heat production during isometric tetanus was larger in the former thanin the latter. These result indicate that the local thermal and mechanical responses during isometric tetanus are not uniform along the entire length of the muscle.