The role of bladder-to-urethral reflexes in urinary continence mechanisms in rats
The role of bladder-to-urethral reflexes in urinary continence mechanisms in rats
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DOI：
10.1152/ajprenal.00038.2004
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发表时间：
2004-09-01
影响因子：
4.2
通讯作者：
Yoshimura, N
中科院分区：
文献类型：
--
作者：
Kamo, I;Cannon, TW;Yoshimura, N
在膀胱内压（P-ves）被动增量过程中的尿道闭合机制进行了研究，使用微尖传感器导管在麻醉的雌性大鼠。在T8-T9处通过脊髓横切阻断反射性膀胱收缩后，突然将P-ves升高至20、40或60 cmH（2）O 2分钟，在中尿道的限制部分（距离尿道口12.5 - 15 mm）诱导膀胱压力依赖性收缩反应，通过切断双侧骨盆神经消除该反应。在盆神经完整的大鼠中，双侧切断阴部神经、髂尾肌/耻尾肌神经或腹下神经均能显著降低（49 ~ 74%）被动性P-ves引起的尿道反射反应，而这三组神经的联合切断则完全消除了尿道关闭反应。在脊髓完整的大鼠中，在P-ves升高（20或40 cmH（2）O）时引起了类似的尿道收缩反应，并且双侧盆神经切断也消除了这种反应。脊髓和盆神经切断后，漏尿点压力（定义为通过以2.5-cmH 2 O步长的膀胱压力钳或直接压迫膀胱的被动P-ves升高过程中导致液体从尿道口泄漏的压力）与假手术（脊髓切断和盆神经完整）大鼠相比显著降低了30 - 35%。这些结果表明：1）被动抬高P-ves可引起盆腔传入神经介导的收缩反射在尿道的限制部分由交感神经和躯体神经的激活介导; 2）被动抬高P-ves引起的膀胱尿道反射显着有助于预防压力性尿失禁。
Urethral closure mechanisms during passive increments in intravesicular pressure (P-ves) were investigated using microtip transducer catheters in urethane-anesthetized female rats. After a block of reflex bladder contractions by spinal cord transection at T8-T9, abruptly raising P-ves to 20, 40, or 60 cmH(2)O for 2 min induced a bladder pressure-dependent contractile response in a restricted portion of the middle urethra (12.5 - 15 mm from the urethral orifice) that was abolished by cutting the pelvic nerves bilaterally. In pelvic nerve-intact rats, the bilateral transection of either the pudendal nerves, the nerves to the iliococcygeous/pubococcygeous muscles, or the hypogastric nerves significantly reduced ( 49 - 74%) the urethral reflex response induced by passive P-ves increases, and combined transection of these three sets of nerves totally abolished the urethra-closing responses. In spinal cord-intact rats, similar urethral contractile responses were elicited during P-ves elevation ( 20 or 40 cmH(2)O) and were also eliminated by bilateral pelvic nerve transection. After spinal cord and pelvic nerve transection, leak point pressures, defined as the pressure inducing fluid leakage from the urethral orifice during passive P-ves elevation by either bladder pressure clamping in 2.5-cmH(2)O steps or direct compression of the bladder, were significantly lowered by 30 - 35% compared with sham-operated ( spinal cord-transected and pelvic nerve-intact) rats. These results indicate that 1) passive elevation of P-ves can elicit pelvic afferent nerve-mediated contractile reflexes in the restricted portion of the urethra mediated by activation of sympathetic and somatic nerves and 2) bladder-to-urethral reflexes induced by passive P-ves elevation significantly contribute to the prevention of stress urinary incontinence.