Role of calcium and calcium modulation in the control of urethral tone.
Role of calcium and calcium modulation in the control of urethral tone.
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钙和钙调节在控制尿道张力中的作用。
DOI：
10.1080/003655901750174836
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Levin,RM
中科院分区：
文献类型：
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作者：
Schroeder,A;Lieb,J;O'Connor,L;Horan,P;Leggett,R;Levin,RM
据估计，尿失禁影响超过1000万美国人，其中85%是女性。45岁以上的妇女中有20%的人大小便失禁，这一比例随着年龄的增长而增加。近50%的失禁患者对目前的治疗方案不满意，32%的患者非常不满意，60%的目前正在接受治疗的女性报告说，她们会尝试任何新的治疗方法（1-3）。本文综述了尿道张力和紧张性α-肾上腺素能张力与女性尿道平滑肌张力的关系，以及钙离子（Ca 2+）和Ca 2+调节在控制尿道平滑肌张力中的作用（显示在图1中）：（i）肾上腺素能神经密度;（ii）α-肾上腺素能受体密度;（iv）钙（Ca 2+）与收缩元件、肌动蛋白和肌球蛋白的相互作用;和（iv）代谢能量的可用性。SM张力对女性尿道阻力的贡献估计为总阻力的30-50%，这明显大于男性（因为前列腺和外括约肌对尿道阻力的贡献）（4-6）。在动物和人类的膀胱充盈期间，尿道的交感神经刺激的进行性增加导致α-肾上腺素能张力增加（7-9）。使用体外兔子完整的“带尿道的膀胱”制备物（图2），我们测量了开始排尿所需的尿道内压（开放压力）、开放压力下排尿的速率和排尿阻力（14-16）。使用该模型的研究结果表明，即使在没有神经支配的情况下，也有足够的α-肾上腺素能张力在膀胱充盈期间维持排尿（14-16）。这些研究证明
It is estimated that incontinence affects more than 10 million Americans, 85% of whom are women. Twenty per cent of women over the age of 45 are incontinent, and the proportion increases with age. Nearly 50% of all incontinence patients are dissatisfi ed with current treatment options, 32% are very dissatisfi ed, and 60% of women currently under treatment report that they would try any novel treatment developed (1–3). This review focuses on the relevance of urethral tone and tonic a-adrenergic tension to the maintainance of continence in women, and the role of calcium (Ca2+) and Ca2+ modulation in the control of urethral smooth muscle (SM) tone.Urethral SM tone is directly related to four factors (displayed in Fig. 1):(i) adrenergic nerve density;(ii) a-adrenergic receptor density;(iv) interaction of calcium (Ca2+) with the contractile elements, actin and myosin; and (iv) availability of metabolic energy. The contribution of SM tone to urethral resistance in females is estimated at 30–50% of the total resistance, which is signifi cantly greater than in the male (because of the contribution of the prostate and external sphinctor to urethral resistance)(4–6). During bladder fi lling in both animals and humans, a progressive increase in sympathetic stimulation of the urethra results in increased a-adrenergic tension (7–9). Using an in vitro rabbit whole “bladder-with-urethra” preparation (Fig. 2), we measured intraurethral pressure required to begin ow (opening pressure), rate of ow at opening pressure, and resistance to ow (14–16). Results of studies using this model showed that, even in the absence of innervation, there was suffi cient a-adrenergic tone to maintain continence during bladder filling (14–16). These studies demonstrated