Involvement of reflex urethral closure mechanisms in urethral resistance under momentary stress condition induced by electrical stimulation of rat abdomen
Involvement of reflex urethral closure mechanisms in urethral resistance under momentary stress condition induced by electrical stimulation of rat abdomen
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DOI：
10.1152/ajprenal.00466.2006
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发表时间：
2007-09-01
影响因子：
4.2
通讯作者：
Hashimoto, Tadatoshi
中科院分区：
文献类型：
--
作者：
Kamo, Izumi;Hashimoto, Tadatoshi
反射性尿道闭合机制参与电刺激大鼠腹部瞬间应激条件下的尿道阻力。美国肾脏生理学杂志293：F920-F926，2007年。首次发表于2007年7月11日; doi：10.1152/ajprenal.00466.2006。- 在乌拉坦麻醉下的脊柱化雌性大鼠中开发了一种用于评估腹压突然升高期间尿道阻力的新方法。电刺激腹部肌肉1 s引起腹内压和膀胱内压以刺激依赖性方式增加，并且当腹部打开时膀胱反应几乎消失。将电刺激过程中引起液体从尿道口渗漏的最低膀胱内压（渗漏点压）和在渗漏点压以下无尿液渗漏的最大膀胱内压作为尿道阻力的指标进行评价。双侧切断盆腔神经或包含阴部神经和髂尾肌/耻尾肌神经的躯体神经后，尿道阻力降低。相反，切断双侧腹下神经的影响较小。压力性尿失禁的药物度洛沙汀可扩大反射性尿道闭合收缩，该收缩是由膀胱内压增加引起的，并使用微尖端传感器导管在尿道中段进行测量。该药物还增加了尿道阻力（漏尿点压力），而在双侧骨盆神经横断的大鼠中没有显示出任何效果，表明该药物增加了反射性尿道闭合导致尿道阻力升高。结果表明，在腹压瞬间升高时，通过膀胱-脊髓-尿道括约肌和骨盆底肌肉的反射性尿道闭合机制对增加尿道阻力以防止尿失禁有很大贡献。
Involvement of reflex urethral closure mechanisms in urethral resistance under momentary stress condition induced by electrical stimulation of rat abdomen. Am J Physiol Renal Physiol 293: F920-F926, 2007. First published July 11, 2007; doi:10.1152/ajprenal.00466.2006. -A novel method for evaluating the urethral resistance during abrupt elevation of abdominal pressure was developed in spinalized female rats under urethane anesthesia. Electrical stimulation of abdominal muscles for 1 s induced increases in both the intra-abdominal and the intravesical pressure in a stimulus-dependent manner, and the bladder response was almost lost when the abdomen was opened. The lowest intravesical pressure during electrical stimulation that induced fluid leakage from the urethral orifice ( leak point pressure) and the maximal intravesical pressure without urine leakage below the leak point pressure were evaluated as the indexes of urethral resistance. Lower urethral resistance was obtained in the rats whose pelvic nerves or somatic nerves containing pudendal nerves and nerves to iliococcygeus/pubococcygeus muscles were transected bilaterally. In contrast, transection of bilateral hypogastric nerves showed smaller effects. Duloxetine, a drug for stress urinary incontinence, enlarged the reflex urethral closing contractions that were induced by an increase in intravesical pressure and measured using a microtip transducer catheter in the middle urethra. This drug also increased the urethral resistance ( leak point pressure), whereas it did not show any effect in the rats whose pelvic nerves were bilaterally transected, showing that the augmentation of the reflex urethral closure by the drug resulted in the elevation of the urethral resistance. From these findings, it was concluded that during momentary elevation of abdominal pressure, the reflex urethral closure mechanisms via bladder-spinal cord-urethral sphincter and pelvic floor muscles greatly contribute to the increase in the urethral resistance to prevent the urinary incontinence.