de Groat William C, Yoshimura Naoki
Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Handb Clin Neurol. 2015;130:61-108. doi: 10.1016/B978-0-444-63247-0.00005-5.
Functions of the lower urinary tract to store and periodically eliminate urine are regulated by a complex neural control system in the brain, spinal cord, and peripheral autonomic ganglia that coordinates the activity of smooth and striated muscles of the bladder and urethral outlet. Neural control of micturition is organized as a hierarchic system in which spinal storage mechanisms are in turn regulated by circuitry in the rostral brainstem that initiates reflex voiding. Input from the forebrain triggers voluntary voiding by modulating the brainstem circuitry. Many neural circuits controlling the lower urinary tract exhibit switch-like patterns of activity that turn on and off in an all-or-none manner. The major component of the micturition switching circuit is a spinobulbospinal parasympathetic reflex pathway that has essential connections in the periaqueductal gray and pontine micturition center. A computer model of this circuit that mimics the switching functions of the bladder and urethra at the onset of micturition is described. Micturition occurs involuntarily during the early postnatal period, after which it is regulated voluntarily. Diseases or injuries of the nervous system in adults cause re-emergence of involuntary micturition, leading to urinary incontinence. The mechanisms underlying these pathologic changes are discussed.
下尿路储存和定期排尿的功能由大脑、脊髓和外周自主神经节中的复杂神经控制系统调节，该系统协调膀胱和尿道出口平滑肌和横纹肌的活动。排尿的神经控制被组织成一个分级系统，其中脊髓储存机制又受延髓上部脑干中启动反射性排尿的神经回路调节。来自前脑的输入通过调节脑干神经回路触发自主排尿。许多控制下尿路的神经回路表现出开关样的活动模式，以全或无的方式开启和关闭。排尿开关回路的主要组成部分是一条脊髓-延髓-脊髓副交感神经反射通路，它在导水管周围灰质和脑桥排尿中枢有重要连接。本文描述了一个模拟排尿开始时膀胱和尿道开关功能的该回路计算机模型。排尿在出生后早期是不自主发生的，之后则受自主调节。成人体内神经系统的疾病或损伤会导致不自主排尿再次出现，从而导致尿失禁。文中讨论了这些病理变化的潜在机制。
