de Groat William C
Department of Pharmacology, University of Pittsburgh Medical School, Pittsburgh, PA 15261, USA.
Br J Pharmacol. 2006 Feb;147 Suppl 2(Suppl 2):S25-40. doi: 10.1038/sj.bjp.0706604.
Storage and periodic expulsion of urine is regulated by a neural control system in the brain and spinal cord that coordinates the reciprocal activity of two functional units in the lower urinary tract (LUT): (a) a reservoir (the urinary bladder) and (b) an outlet (bladder neck, urethra and striated muscles of the urethral sphincter). Control of the bladder and urethral outlet is dependent on three sets of peripheral nerves: parasympathetic, sympathetic and somatic nerves that contain afferent as well as efferent pathways. Afferent neurons innervating the bladder have A-delta or C-fibre axons. Urine storage reflexes are organized in the spinal cord, whereas voiding reflexes are mediated by a spinobulbospinal pathway passing through a coordination centre (the pontine micturition centre) located in the brainstem. Storage and voiding reflexes are activated by mechanosensitive A-delta afferents that respond to bladder distension. Many neurotransmitters including acetylcholine, norepinephrine, dopamine, serotonin, excitatory and inhibitory amino acids, adenosine triphosphate, nitric oxide and neuropeptides are involved in the neural control of the LUT. Injuries or diseases of the nervous system as well as disorders of the peripheral organs can produce LUT dysfunctions including: (1) urinary frequency, urgency and incontinence or (2) inefficient voiding and urinary retention. Neurogenic detrusor overactivity is triggered by C-fibre bladder afferent axons, many of which terminate in the close proximity to the urothelium. The urothelial cells exhibit 'neuron-like' properties that allow them to respond to mechanical and chemical stimuli and to release transmitters that can modulate the activity of afferent nerves.
尿液的储存和周期性排出由大脑和脊髓中的神经控制系统调节，该系统协调下尿路（LUT）中两个功能单元的相互活动：（a）一个储存器（膀胱）和（b）一个出口（膀胱颈、尿道和尿道括约肌的横纹肌）。膀胱和尿道出口的控制依赖于三组外周神经：副交感神经、交感神经和躯体神经，它们包含传入和传出通路。支配膀胱的传入神经元具有A-δ或C纤维轴突。尿液储存反射在脊髓中组织，而排尿反射由穿过位于脑干的协调中心（脑桥排尿中心）的脊髓-延髓-脊髓通路介导。储存和排尿反射由对膀胱扩张作出反应的机械敏感A-δ传入神经激活。许多神经递质，包括乙酰胆碱、去甲肾上腺素、多巴胺、5-羟色胺、兴奋性和抑制性氨基酸、三磷酸腺苷、一氧化氮和神经肽，都参与了下尿路的神经控制。神经系统的损伤或疾病以及外周器官的紊乱可导致下尿路功能障碍，包括：（1）尿频、尿急和尿失禁，或（2）排尿效率低下和尿潴留。神经源性逼尿肌过度活动由C纤维膀胱传入轴突触发，其中许多轴突在靠近尿路上皮的地方终止。尿路上皮细胞表现出“神经元样”特性，使它们能够对机械和化学刺激作出反应，并释放可调节传入神经活动的递质。
