Sugaya Kimio, DE Groat William C
Division of Urology, Department of Organ-oriented Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa, Japan.
Low Urin Tract Symptoms. 2009 Jun;1(1):51-55. doi: 10.1111/j.1757-5672.2009.00004.x.
This study was undertaken to investigate whether chronic bladder outlet obstruction (BOO) in female rats influences the tonic parasympathetic excitatory or inhibitory reflex control of bladder activity. METHODS: Bladder activity during isovolumetric cystometry (1.5-12 mL) was examined after transection of dorsal and ventral lumbosacral spinal roots (L4-S4) and administration of hexamethonium, a ganglionic blocking agent, in urethane anesthetized female rats with sympathectomy and BOO. RESULTS: Lumbosacral dorsal root transection abolished reflex bladder contractions, but did not influence intravesical baseline pressure. However, ventral root transection after dorsal root transection decreased baseline intravesical pressure (y: % change) at low bladder volumes (x) and increased pressure at high volumes. The calculated (y = 1.9x - 16.5) transition volume was 9 mL. Administration of hexamethonium (100 mg/kg, intraperitoneally) after dorsal and ventral root transection increased the amplitude and decreased the frequency of myogenic bladder contractions. CONCLUSION: The bladder is tonically excited or inhibited depending upon bladder volume by the interactions between a parasympathetic preganglionic pathway in the pelvic nerve and a peripheral reflex. However, in rats with BOO, the volume at which the response shifts from excitation to inhibition was very large, and tonic function of the parasympathetic preganglionic pathway was weak compared to previously reported results in rats without BOO. The persistence of reflex tonic excitatory control of bladder tone over a broad range of bladder volumes may be one of the reasons for overactivity of the bladder with outlet obstruction.
本研究旨在探讨雌性大鼠慢性膀胱出口梗阻（BOO）是否会影响膀胱活动的紧张性副交感神经兴奋性或抑制性反射控制。方法：在对接受交感神经切除术和BOO的雌性大鼠进行氨基甲酸乙酯麻醉后，切断腰骶部背侧和腹侧脊髓神经根（L4-S4）并给予神经节阻断剂六甲铵，然后检查等容膀胱测压（1.5-12 mL）期间的膀胱活动。结果：腰骶部背根切断消除了反射性膀胱收缩，但不影响膀胱内基线压力。然而，在背根切断后进行腹根切断，在低膀胱容量（x）时降低了膀胱内基线压力（y：变化百分比），在高容量时增加了压力。计算得出的（y = 1.9x - 16.5）转换容量为9 mL。在背根和腹根切断后给予六甲铵（100 mg/kg，腹腔注射）增加了肌源性膀胱收缩的幅度并降低了频率。结论：膀胱通过盆神经中的副交感神经节前通路与外周反射之间的相互作用，根据膀胱容量受到紧张性兴奋或抑制。然而，在患有BOO的大鼠中，反应从兴奋转变为抑制的容量非常大，并且与先前报道的无BOO大鼠的结果相比，副交感神经节前通路的紧张性功能较弱。在广泛的膀胱容量范围内，膀胱张力的反射性紧张性兴奋控制持续存在可能是膀胱出口梗阻时膀胱过度活动的原因之一。
