正常猫膈神经单纤维电活动特征

在麻醉猫和麻痹的切断迷走神经的清醒猫,观察了膈神经单纤维电活动特征。1.电活动类型:按膈神经单纤维放电与其总干放电的相位关系分为三种类型。(1)完全同步型,即单纤维放电与总干放电同时开始并同时停止,占76.9％。(2)部分同步型占15.4％,其中早期同步,即单纤维放电与总干放电同时开始,但提前终止,占1.9％,中期同步,即单纤维放电较总干放电开始晚,又提前终止,占5.8％,晚期同步,即单纤维放电较总干放电开始晚,但两者同时终止,占7.7％。(8)非同步型,即吸气相和呼气相都有放电,但呼气相时冲动频率较低,占7.7％。前两型为单纯的吸气性放电,共占92.3％。2.单纤维放电平均参数值:麻醉猫每次吸气发放11个冲动,其频率为21次/秒,清醒猫每次吸气发放18个冲动,其频率为34次/秒。结果表明:猫膈神经单纤维放电类型和文献上报导的直接记录膈神经运动神经元放电一致,即以单纯的吸气性放电为最多。

CHARACTERISTICS OF SINGLE FIBRE DISCHARGES IN THE PHRENIC NERVE OF THE CAT

In 27 urethane-anesthetized and 25 tubocurarine-paralyzed, vagotomi-zed and artificially ventilated cats, the discharges of the single fibres and whole trunk of phrenic nerve were recorded.1. The patterns of the discharges recorded in the single fibres may be classified into five types according to the phases of the cycle during which they fired as indicated by the whole phrenic nerve discharges-( 1 Hypical inspiratory discharges ( 76.9% ) commenced and ceased firing at the begining and the end of inspiration respectively; (2)early inspiratory discharges ( 1.9% ) ceased firing before the end of inspirations (3) late inspiratory discharges ( 7.7% ) commenced firing after the begining of inspiration; ( 4 )middle inspiratory discharges ( 5.8%)only fired at the middle of imspiration; ( 5 )inspiratory continuous discharges ( 7.7 ) fired continuously through the respiratory cycle, but had a higher frequency during inspiration.2. In anesthetized cats, the discharges of the single fibre consisted of 11 impulses per cycle and average impulse frequency was 21 Hz. But in unane thetized,paralyzed cats, the discharges consisted of 18 impulses per cycle and the average impulse frequency was 34 Hz.These results indicated that characteristics of discharge patterns of single fibre in the phrenic nerve of cat were similar to those of the phrenic motoneurones recorded by microelectrode in spinal cord.