Urinary bladder dysfunction might be related to disturbances at different levels of the micturition reflex arc. The current study aimed to further develop and evaluate a split bladder model for detecting and analysing relaxatory signalling in the rat urinary bladder. The model allows for discrimination between effects at the efferent and the afferent side of the innervation. In experiments, the stimulation at a low frequency (1 Hz) of the ipsilateral pelvic nerve tended to evoke relaxation of the split bladder half (contralateral side; −1.0 ± 0.4 mN; = 5), in contrast to high frequency-evoked contractions. In preparations in which the contralateral pelvic nerve was cut the relaxation occurred at a wider range of frequencies (0.5–2 Hz). In separate experiments, responses to 1 and 2 Hz were studied before and after intravenous injections of propranolol (1 mg/kg IV). The presence of propranolol significantly shifted the relaxations into contractions. Also, electrical stimulation of the ipsilateral pudendal nerve evoked relaxations of similar magnitude as for the pelvic stimulations, which were also affected by propranolol. In control experiments, substances with β-adrenoceptor agonism, in contrast to a selective α-agonist, evoked relaxations. The current study shows that the split bladder model can be used for studies of relaxations. In the model, reflex-evoked sympathetic responses caused relaxations at low intensity stimulation. The involvement of β-adrenoceptors is supported by the sensitivity to propranolol and by the observations.

中文翻译：

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刺激大鼠盆腔和阴部感觉神经引起的原位膀胱模型中的肾上腺素能松弛


膀胱功能障碍可能与排尿反射弧不同水平的紊乱有关。当前的研究旨在进一步开发和评估用于检测和分析大鼠膀胱松弛信号的分裂膀胱模型。该模型允许区分神经支配的传出侧和传入侧的效应。在实验中，低频（1 Hz）刺激同侧骨盆神经往往会引起半部膀胱的松弛（对侧；-1.0 ± 0.4 mN；= 5），与高频引起的收缩相反。在对侧骨盆神经被切断的准备工作中，松弛发生在更宽的频率范围（0.5-2 Hz）。在单独的实验中，研究了静脉注射普萘洛尔（1 mg/kg IV）之前和之后对 1 Hz 和 2 Hz 的反应。普萘洛尔的存在显着地将松弛转变为收缩。此外，同侧阴部神经的电刺激引起与骨盆刺激相似程度的松弛，这也受到普萘洛尔的影响。在对照实验中，与选择性α-激动剂相比，具有β-肾上腺素受体激动剂的物质会引起放松。目前的研究表明，分裂膀胱模型可用于松弛研究。在模型中，反射诱发的交感神经反应在低强度刺激下引起松弛。对普萘洛尔的敏感性和观察结果支持β-肾上腺素受体的参与。