Onda Akiko, Uchida Sae, Suzuki Harue, Hotta Harumi
Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo, 173-0015, Japan.
Division of Rheumatology and Allergy, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, 173-8606, Japan.
J Physiol Sci. 2016 Nov;66(6):491-496. doi: 10.1007/s12576-016-0468-x. Epub 2016 Jul 6.
We aimed to examine the afferent mechanisms for the reflex inhibition of the rhythmic micturition contractions (RMCs) of the urinary bladder induced by stimulation of the perineal skin afferents in urethane-anesthetized rats. Electrical stimulation (pulse duration: 0.5 ms) was applied to the cutaneous branches of the pudendal nerve (CBPN) at frequencies of 0.1, 1, and 10 Hz for 1 min. Nerve fiber groups were defined by recording compound action potentials from CBPN. Activation of only Aβ fibers (0.2 V) produced an inhibition of RMCs at 7-11 min after the onset of stimulation (late inhibition), at any tested frequency. Additional activation of Aδ fibers (1 V) produced additional early inhibition (immediately after stimulation) at 1 and 10 Hz. Furthermore, additional activation of C fibers (10 V) at 10 Hz completely stopped RMCs for >10 min. This strong inhibition persisted after local application of capsaicin to the stimulating CBPN. We conclude that activities of Aβ, Aδ, and C afferent fibers, without capsaicin-sensitive channels, can contribute to the inhibition of bladder contractions.
我们旨在研究在乌拉坦麻醉的大鼠中，刺激会阴皮肤传入神经所诱导的膀胱节律性排尿收缩（RMCs）反射抑制的传入机制。以0.1、1和10Hz的频率对阴部神经的皮支（CBPN）施加电刺激（脉冲持续时间：0.5ms），持续1分钟。通过记录CBPN的复合动作电位来定义神经纤维组。仅激活Aβ纤维（0.2V）在刺激开始后7 - 11分钟（延迟抑制）时，在任何测试频率下均产生RMCs的抑制。额外激活Aδ纤维（1V）在1和10Hz时产生额外的早期抑制（刺激后立即出现）。此外，在10Hz时额外激活C纤维（10V）可使RMCs完全停止超过10分钟。在向刺激的CBPN局部应用辣椒素后，这种强烈的抑制仍然存在。我们得出结论，Aβ、Aδ和C传入纤维的活动（无辣椒素敏感通道）可导致膀胱收缩的抑制。
