FUNCTIONAL-CHARACTERISTICS OF LUMBAR VISCERAL AFFERENT-FIBERS FROM THE URINARY-BLADDER AND THE URETHRA IN THE CAT
FUNCTIONAL-CHARACTERISTICS OF LUMBAR VISCERAL AFFERENT-FIBERS FROM THE URINARY-BLADDER AND THE URETHRA IN THE CAT
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DOI：
10.1007/bf00657509
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发表时间：
1986-11-01
影响因子：
4.5
通讯作者：
NELKE, A
中科院分区：
文献类型：
--
作者：
BAHNS, E;ERNSBERGER, U;NELKE, A
本文系统地分析了猫膀胱和尿道的腰内脏传入神经的活动。在闭合腹腔的制备中，从L3和L4的白色支分离传入纤维，或在开放腹腔的制备中从腰内脏神经分离传入纤维，并研究了各种功能参数。分析了75个单单位和9个多单位束。1)大约50%的传入单位有一些持续的活动（0.2 tp 1 imp/s）。三分之二的传入轴突是薄的髓鞘（传导速度3-15 m/s），其余的可能是无髓鞘的（传导速度低于2 m/s）。2)传入单位的感受野由膀胱和尿道表面的单个机械敏感部位组成，只有一个例外。大多数感受野位于膀胱背侧。3)在膀胱壁上或膀胱壁中的感受野传入神经以分级的方式对被动扩张和等容收缩作出反应，膀胱内压力范围为约10至70 mm Hg。刺激传入单位的阈值范围从小于10 mm Hg到约30 mm Hg膀胱内压，其中大多数小于20 mm Hg。一般来说，传入单位的放电率给出了一个可靠的代表膀胱内压的腰髓。4)尿道单位表现出没有反应的分级扩张和收缩的膀胱，或响应与低排放率在较高的膀胱内压。5)这些结果不支持膀胱中的伤害性事件是由腰髓的“特异性”伤害性内脏传入神经编码的观点，但可能是由其他一些编码机制编码的。
Neural activity of lumbar visceral afferents supplying the urinary bladder and urethra was analyzed systematically in the cat. The afferent fibers were isolated either from the white rami L3 and L4 in a preparation with closed peritoneal cavity, or from the lumbar splanchnic nerves in a preparation with open peritoneal cavity and investigated for various functional parameters. Seventy five single units and 9 multiunit bundles were analyzed. 1) About 50% of the afferent units had some ongoing activity (0.2 tp 1 imp/s). Two thirds of the afferent axons were thin myelinated (conduction velocity 3-15 m/s), the rest were presumably unmyelinated (conduction velocity below 2 m/s). 2) The receptive fields of the afferent units consisted.sbd.with one exception.sbd.of single mechanosensitive sites on the surface of bladder and urethra. Most receptive fields were situated on the dorsal side of the bladder. 3) Afferents with receptive fields on or in the bladder wall responded in a graded manner to passive distension and isovolumetric contraction at intravesical pressures ranging from about 10 to 70 mm Hg. The thresholds for exciting the afferent units ranged from less than 10 mm Hg to about 30 mm Hg intravesical pressure, most of them being less than 20 mm Hg. Generally, the discharge rate of the afferent units gave a reliable representation of the intravesical pressure to the lumbar spinal cord. 4) Urethral units exhibited either no responses to the graded distensions and contractions of the urinary bladder, or responded with low discharge rates at higher intravesical pressures. 5) The results do not support the notion that noxious events in the urinary bladder are encoded by "specific" nociceptive visceral afferents to the lumbar spinal cord but possibly by some other mechanism of encoding.