Gerstenberg T C, Levin R J, Wagner G
Institute of Medical Physiology B, Panum Institute, Copenhagen, Denmark.
Br J Urol. 1990 Apr;65(4):395-402. doi: 10.1111/j.1464-410x.1990.tb14764.x.
Electromyographic (EMG) recordings were obtained by concentric needle electrodes from the bulbocavernosus (BC) and ischiocavernosus (IC) muscles in 7 human volunteers during excitement to erection and subsequent ejaculation. Simultaneous registration of the time course and volume of each expressed spurt of semen was obtained using an aluminium pan suspended in front of the subject's penis on a force transducer the output of which was charted with the EMG activity. The BC and IC muscles showed no EMG activity during erection and detumescence cycles induced by visual sex stimulation. In 5 of 7 subjects, the first EMG burst of the BC in ejaculations induced by masturbation was not correlated with an expelled spurt of semen as were subsequent bursts. However, only 26 to 60% of the total number of EMG bursts were accompanied by expulsion of a spurt of semen. There thus appears to be a large safety factor in the striated muscle expulsive mechanism. Oral phenoxybenzamine treatment in 2 subjects did not significantly affect either the number of EMG bursts of the BC or the subjective pleasure of the orgasm but did significantly reduce the volume of semen expelled. Semen volume does not appear to be a unique determinant of the pleasure felt or the trigger for ejaculation.
通过同心针电极在7名人类志愿者兴奋勃起及随后射精过程中获取球海绵体肌（BC）和坐骨海绵体肌（IC）的肌电图（EMG）记录。使用一个悬挂在受试者阴茎前方力传感器上的铝盘，同时记录每次射出精液的时间过程和体积，该力传感器的输出与EMG活动一起记录在图表上。在视觉性刺激诱发的勃起和消肿周期中，BC和IC肌肉未显示EMG活动。在7名受试者中的5名中，手淫诱发射精时BC的第一次EMG爆发与随后的爆发不同，与射出的精液喷射并无关联。然而，EMG爆发总数中只有26%至60%伴随着精液喷射。因此，横纹肌排出机制似乎存在很大的安全系数。对2名受试者进行口服酚苄明治疗，对BC的EMG爆发次数或性高潮的主观愉悦感均无显著影响，但显著减少了射出的精液量。精液量似乎并非所感受到愉悦或射精触发的唯一决定因素。
