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Effects of stimulation frequency, calcium concentration and temperature on the force-velocity relations of bullfrog atrial muscle

Chen Xiaoliang

Department of Physiology, Capital Institute of Medicine

Abstract

Force-velocity relations are studied in isolated atrial muscle of the bullfrog at low temperature (4.5±2℃)using an afterload method. 62 force-velocity curves
were obtained in 14 atrial muscles. It was found that none of the force-velocity
curves was hyperbolic. Effects of stimulation frequency (6-24/min), calcium
concentration (1.8-9 mmol/L) and temperature (2.5-1810)on the force-velocity
curve were also observed in 12 atrial muscle preparations. The results showed
that all the curves could not fit Hill's equation, although some changes did occur.If the curves were carefully Compared with hyperbolic curve it can be seen that the curve shifted upwards with the increment of afterload. This change might be related to the status of cardiac activity. In the present paper, relations between the force-velocity curve and the active state were discussed.

Key words: Force-velocity relation;Cardiac muscle;Frequency;Calcium;Temperature

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Citing This Article：

Chen Xiaoliang. Effects of stimulation frequency, calcium concentration and temperature on the force-velocity relations of bullfrog atrial muscle. Acta Physiol Sin 1987; 39 (2): (in Chinese with English abstract).