Krier J
J Physiol. 1985 Nov;368:471-80. doi: 10.1113/jphysiol.1985.sp015869.
Segmental somatic reflexes to pudendal motor axons which innervate the skeletal muscle of the external anal sphincter were studied in cats with an intact spinal cord and in acutely spinalized cats (T13-L2 spinal cord transection level) during electrical stimulation of afferent fibres in the pudendal nerve, during distension of the anal canal and reproductive organs, and during tactile (light touch and pressure) and nociceptive stimuli (pinch) applied to the mucosa of the anal canal, anal-perianal skin region, and the skin surrounding reproductive organs. Forty single pudendal motor axons recorded from nerve filaments in the pudendal nerve branch to the external anal sphincter which responded reflexly to electrical stimulation of afferent fibres in the contralateral pudendal nerve were studied. Only one motor axon was spontaneously active. 70% of these motor axons were also activated by distension of the anal canal and reproductive organs and by mechanical stimulation of the skin. 61% of motor axons which were activated by distension of the anal canal were also activated by mechanical stimulation of the mucosa of the anal canal, anal-perianal skin region. 29% of motor axons were activated by convergent afferent inputs (during distension and mechanical stimulation) from both reproductive organs and from the external anal sphincter region. Motor axons exhibited bursts of action potentials during reflexes initiated during distension of the anal canal and vagina. Motor axons exhibited phasic discharges of action potentials during reflexes initiated by tactile or nociceptive stimuli applied to the mucosa of the anal canal, anal-perianal skin region and the skin surrounding reproductive organs. The peak firing frequencies of action potentials during mechanical stimulation of the skin ranged from 8 to 35 Hz. The average firing frequencies of action potentials during continuous distension of the anal canal ranged from 4 to 16 Hz.
在完整脊髓的猫以及急性脊髓损伤猫（T13-L2脊髓横断水平）中，研究了支配肛门外括约肌骨骼肌的阴部运动轴突的节段性躯体反射。研究过程包括：在电刺激阴部神经的传入纤维时、在肛管和生殖器官扩张时、以及在对肛管黏膜、肛门-肛周皮肤区域和生殖器官周围皮肤施加触觉（轻触和压力）和伤害性刺激（捏）时。从阴部神经分支至肛门外括约肌的神经细丝中记录了40条单个阴部运动轴突，这些轴突对同侧阴部神经传入纤维的电刺激有反射反应。只有一条运动轴突自发活动。其中70%的运动轴突也会因肛管和生殖器官的扩张以及皮肤的机械刺激而被激活。61%因肛管扩张而被激活的运动轴突，也会因肛管黏膜、肛门-肛周皮肤区域的机械刺激而被激活。29%的运动轴突会被来自生殖器官和肛门外括约肌区域的汇聚传入输入（在扩张和机械刺激期间）激活。在肛管和阴道扩张引发的反射过程中，运动轴突会出现动作电位爆发。在对肛管黏膜、肛门-肛周皮肤区域和生殖器官周围皮肤施加触觉或伤害性刺激引发的反射过程中，运动轴突会出现动作电位的相位性放电。皮肤机械刺激期间动作电位的峰值放电频率范围为8至35赫兹。肛管持续扩张期间动作电位的平均放电频率范围为4至16赫兹。
