Enhancement of twitch force by stretch in a nerve-skeletal muscle preparation of the frogRana porosa brevipodaand the effects of temperature on it

Abstract

SUMMARY We investigated the mechanism of the enhancement of twitch force by stretch and the effects of temperature on it in nerve-skeletal muscle preparations of whole iliofibularis muscles isolated from the frog Rana brevipoda. When a preparation was stimulated indirectly and stretched, the twitch force after the stretch was enhanced remarkably in comparison to that observed before a stretch at low temperature. The enhanced force obtained by a stretch of 20% resting muscle length (l0) at low temperature was as high as the force obtained by direct stimulation. The phenomenon was not dependent on the velocity but on the amplitude of stretch. The enhanced force obeyed the length-force relationship when a stretch was long enough. The above results were observed when the frogs were kept at room temperature(20-22°C). Measurements were also taken at low temperature (4°C); when frogs were kept at low temperature for more than 2 months, twitch force obtained without stretch was considerably higher at l0. The amplitude of the action potential recorded extracellularly from the muscle surface increased remarkably after a stretch, but was same before and after a stretch when recorded from the nerve innervating muscle. The effects of temperature on twitch and tetanic force by direct or indirect stimulation without stretch were also studied as basic data of the stretch experiment. The results from this study suggest that stretch-induced force enhancement in a nerve-muscle preparation is caused by an increase in the transmission rate between nerve and muscle, and the amplitude of the enhanced force is determined by the length-force relationship of the muscle. The phenomenon is also strongly affected by the temperature at which the frogs are kept.

Effect of temperature on residual force enhancement in single skeletal muscle fibers

“…However, our observations are not novel. Ishii et al (2004) and Renaud and Stevens, (1981) also found essentially constant forces in frog skeletal muscles across a large range of temperatures. Frogs in these latter studies, like ours, were kept in a cold environment (about 5 1C) prior to testing, and it appears that frog muscles adapt to cold environments such that force can be kept constant over a large range of temperatures (Ishii et al, 2004).…”

Characteristics of Tetanic Force Produced by the Sternomastoid Muscle of the Rat

“…Although changes in muscle temperatures above 25°C significantly influence twitch force, they only have a small influence on tetanic force [27, 28]. To reduce the variability of collected force data, the temperature of the SM muscle was monitored regularly and maintained between 35-36°C.…”

Effects of temperature on maximum acceleration, deceleration and power output during vertical running in geckos

“…Temperature has been shown to affect many aspects of vertebrate function, including muscle contraction frequency, the maximum speed of locomotion, gas exchange and digestion rate (Huey and Bennett, 1987;Huey and Kingsolver, 1989;DeNardo et al, 2002;Ishii et al, 2004;Sollid et al, 2005). The effects of temperature on steady speed locomotion have been fairly well studied, particularly in ectotherms such as lizards and fish (Huey and Bennett, 1987;Garland, Jr and Losos, 1994).…”