Department of Surgery, University of Connecticut Health Center, Farmington, Connecticut 06030, USA.
Neurourol Urodyn. 2012 Jan;31(1):30-5. doi: 10.1002/nau.21223. Epub 2011 Oct 28.
Bladder compliance is one expression of the pressure and volume relationship as the bladder fills. In addition to passive elements, autonomous micromotional detrusor activity contributes to this relationship. In the mouse cystometric model, compliance pressure contributes to voiding expulsive pressure. During attempts to isolate the detrusor contractile component of this filling pressurization, we found that compliance reversibly diminishes under conditions which remove central control from the micturition cycle.
Ten mature female mice underwent constant infusion pressure/flow cystometry under urethane anesthesia, and five awake mature female mice underwent constant infusion pressure cystometry. Following baseline cystometry, all mice were anesthetized with isoflurane to abolish the micturition reflex, and cystometry conducted with manual emptying of the bladders. Animals were then allowed to recover from isoflurane to re-establish the micturition reflex, and cystometry again conducted. The urethane group was also studied immediately post-mortem. Repeated measures comparisons of cystometric parameters were made across conditions.
Compliance reversibly decreased in all mice with the abolishment of micturition responses by isoflurane anesthesia. A similar decrease was observed immediately post-mortem in the urethaned mice. Bladder filling and voiding were not different between the intact micturition segments of the testing.
Enhanced compliance in mice with intact micturition responses suggests that autonomous micromotional activity is suppressed by central processes during normal filling. Since afferent activity during filling is also determined by the relationship between bladder pressure and volume, a feed-forward afferent signal conditioning mechanism may exist, creating novel therapeutic targets for urinary dysfunctions.
膀胱顺应性是膀胱充盈时压力与容积关系的一种表现。除了被动因素外，自主的微量逼尿肌活动也对这种关系有贡献。在小鼠尿动力学模型中，顺应性压力有助于排空时的逼尿肌收缩压力。在试图分离充盈加压时逼尿肌收缩成分的过程中，我们发现顺应性在去除排尿反射的中枢控制的情况下可逆性地降低。
10 只成熟雌性小鼠在乌拉坦麻醉下进行恒压/流量尿动力学检查，5 只清醒成熟雌性小鼠进行恒压尿动力学检查。基线尿动力学检查后，所有小鼠均用异氟烷麻醉以消除排尿反射，并进行手动排空膀胱的尿动力学检查。然后让动物从异氟烷中恢复以重新建立排尿反射，并再次进行尿动力学检查。该组还在死后立即进行研究。在不同条件下对尿动力学参数进行重复测量比较。
所有小鼠的排尿反射被异氟烷麻醉消除后，顺应性均可逆性降低。在麻醉的乌拉坦小鼠中也观察到类似的降低。在完整的排尿段测试中，膀胱充盈和排空没有差异。
在有完整排尿反应的小鼠中，顺应性增强表明自主的微量运动活动在正常充盈过程中受到中枢过程的抑制。由于充盈期间的传入活动也取决于膀胱压力和容积之间的关系，因此可能存在一种前馈传入信号调节机制，为尿功能障碍创造新的治疗靶点。
