Saphenous (SAFN) nerve stimulation was recently shown in anesthetized rats to elicit bladder-inhibitory responses in a frequency-dependent manner; however, the mechanism of action is unknown. The goal of this study was to investigate the potential role of the hypogastric nerve (HGN) in this inhibitory pathway by examining stimulation-evoked changes in bladder function under four different experimental conditions: (1) HGN intact, saline infusion (HGNi-s), (2) HGN transected, saline infusion (HGNt-s), (3) HGN intact, acetic acid (AA) infusion (HGNi-a), and (4) HGN transected, AA infusion (HGNt-a). Experiments were conducted in 33 urethane-anesthetized female rats, where continuous bladder infusion was provided through a suprapubic catheter. The experimental protocol involved two, 40-min stimulation trials in which electrical pulses were applied to the SAFN at a set frequency (10 Hz) and two different amplitudes (50 μA and 100 μA). In all experimental groups, SAFN stimulation resulted in complete suppression of bladder activity with an incidence rate of 25% to 50%. However, significant changes in the measured urodynamic changes (e.g., basal pressure, contraction amplitude, and inter-contraction interval) were found only in the HGNt-a animals. Our findings suggest that the HGN does not mediate the inhibitory effects of SAFN stimulation and that bladder inhibition is achieved through a different mechanism of action.

中文翻译：

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横切下腹神经以揭示与麻醉大鼠隐神经刺激有关的膀胱抑制通路

最近在麻醉大鼠中显示隐静脉 (SAFN) 神经刺激以频率依赖的方式引起膀胱抑制反应；然而，作用机制尚不清楚。本研究的目的是通过检查在四种不同实验条件下刺激诱发的膀胱功能变化来研究下腹神经 (HGN) 在该抑制途径中的潜在作用：(1) HGN 完整、盐水输注 (HGNi-s) ，(2) HGN 横切，盐水输注 (HGNt-s)，(3) HGN 完整，醋酸 (AA) 输注 (HGNi-a)，和 (4) HGN 横切，AA 输注 (HGNt-a)。实验在 33 只氨基甲酸乙酯麻醉的雌性大鼠中进行，其中通过耻骨上导管提供连续膀胱输液。实验方案涉及两个，40 分钟的刺激试验，其中以设定的频率 (10 Hz) 和两种不同的幅度（50 μA 和 100 μA）向 SAFN 施加电脉冲。在所有实验组中，SAFN 刺激导致膀胱活动完全抑制，发生率为 25% 至 50%。然而，仅在 HGNt-a 动物中发现了测量的尿动力学变化（例如，基础压力、收缩幅度和收缩间隔）的显着变化。我们的研究结果表明，HGN 不介导 SAFN 刺激的抑制作用，膀胱抑制是通过不同的作用机制实现的。SAFN 刺激导致膀胱活动完全抑制，发生率为 25% 至 50%。然而，仅在 HGNt-a 动物中发现了测量的尿动力学变化（例如，基础压力、收缩幅度和收缩间隔）的显着变化。我们的研究结果表明，HGN 不介导 SAFN 刺激的抑制作用，膀胱抑制是通过不同的作用机制实现的。SAFN 刺激导致膀胱活动完全抑制，发生率为 25% 至 50%。然而，仅在 HGNt-a 动物中发现了测量的尿动力学变化（例如，基础压力、收缩幅度和收缩间隔）的显着变化。我们的研究结果表明，HGN 不介导 SAFN 刺激的抑制作用，膀胱抑制是通过不同的作用机制实现的。