Cevese A, Poltronieri R, Schena F, Verlato G, Zaffagni C
Boll Soc Ital Biol Sper. 1984 Nov 30;60(11):2009-16.
Efferent cervical vagal stimulations were performed in 4 anesthetized dogs, either with trains of stimuli of constant frequency (CONT), or with brief trains, triggered by the atrial electrical activity (TRIG). Heart rate was increased by cardiac pacing during vagal stimulations. Negative inotropic effects of vagal stimulations, evaluated as changes in atrial contractility, were partially inhibited by cardiac acceleration during CONT, but were unaffected during TRIG. It is concluded that the number of stimuli per cycle, not the number of stimuli per second, is the critical factor for parasympathetic heart regulation.
对4只麻醉犬进行颈迷走神经传出刺激，刺激方式分为两种：一种是采用恒定频率的刺激串（CONT），另一种是由心房电活动触发的短刺激串（TRIG）。在迷走神经刺激期间通过心脏起搏使心率增加。迷走神经刺激的负性变力作用通过心房收缩性的变化来评估，在CONT期间心脏加速可部分抑制这种作用，但在TRIG期间则不受影响。得出的结论是，每个心动周期的刺激次数而非每秒的刺激次数是副交感神经对心脏调节的关键因素。
