口蓋帆張筋の機械的収縮特性

Abstract

This study was intended to clarify the mechanical contraction properties of the tensor veli palatini muscle in dogs. Twenty adult dogs were used under an intraperitoneum anesthesia of the pentobarbital sodium. The tension of the tensor veli paltini muscle was recorded by electrical stimulation to the motor nerve.Results were as follows:1. The contraction time and half relaxation time of maximal isometric twitch of the muscle were calculated as 13.7±0.7 msec and 10.4±1.2 msec, respectively.2. A clear summation of muscle contractions was obtained with stimulation at 20 Hz and maximal tetanic tension was at 90 Hz. The tetanus twitch tension ratio wasfound to be 10.7±1.1.3. The maximum rate of tension rise was observed at 150 Hz and value was 2.5±0.5 times as long as the rate of a twitch contraction.4. The contraction rate of an isotonic twitch was 3.2±0.7% and the maximum contraction rate was obtained at 80 Hz which was 26.3±1.9%.