Maggi C A
Pharmacology Department, A. Menarini Pharmaceuticals, Florence, Italy.
Ciba Found Symp. 1990;151:77-83; discussion 83-90. doi: 10.1002/9780470513941.ch5.
The sensory innervation of the urinary bladder and urethra plays a key role in a variety of reflexes involved in urine storage and voiding. Dysfunction of these systems is a possible cause of many disturbances related to urine continence but basic knowledge in this field has been hampered by the lack of tools for studying sensory nerves. The use of capsaicin, the pungent ingredient of red peppers, allowed us to investigate the anatomical and functional properties of a specific subset of sensory neurons in the lower urinary tract. These 'capsaicin-sensitive' neurons play a dual sensory and 'efferent' function, determined by transmitter release from their central and peripheral nerve endings. Tachykinins, including substance P, and other neuropeptides such as calcitonin gene-related peptide, mediate the functions of these sensory neurons. The 'sensory' function includes regulation of micturition threshold, activation of cardiovascular reflexes and perception of pain from the urinary bladder. The 'efferent' function includes local regulation of muscle cell activity, nerve excitability, blood flow and plasma protein extravasation. Recent data suggest that capsaicin-sensitive sensory nerves could be present in the human bladder.
膀胱和尿道的感觉神经支配在参与尿液储存和排尿的各种反射中起关键作用。这些系统的功能障碍可能是许多与尿失禁相关紊乱的一个原因，但该领域的基础知识因缺乏研究感觉神经的工具而受到阻碍。辣椒素（红辣椒的辛辣成分）的使用使我们能够研究下尿路中特定感觉神经元子集的解剖学和功能特性。这些“辣椒素敏感”神经元具有双重感觉和“传出”功能，这取决于它们中枢和外周神经末梢释放的递质。速激肽，包括P物质，以及其他神经肽，如降钙素基因相关肽，介导这些感觉神经元的功能。“感觉”功能包括调节排尿阈值、激活心血管反射以及感知膀胱疼痛。“传出”功能包括对肌肉细胞活动、神经兴奋性、血流和血浆蛋白外渗的局部调节。最近的数据表明，辣椒素敏感的感觉神经可能存在于人类膀胱中。
