Role of renal afferent nerve in the regulation of blood pressure

肾脏通过水和钠的代谢以及通过体液因子如肾素-血管紧张素系统在全身血压的调节中起重要作用。然而，关于肾传入神经的作用的信息很少。本研究以Wistar-Kyoto大鼠（WKY）和自发性高血压大鼠（SHR）为研究对象，探讨肾传入神经在血压调节中的作用。[方法]选用13 ~ 15周龄WKY和SHR为研究对象。在戊巴比妥麻醉下，通过腹部中线切口暴露左肾交感神经。矩形脉冲被递送到肾神经。频率在1和20 Hz之间变化，而刺激的电压和持续时间保持恒定（分别为10 V和1 msec）。为了记录肾传入神经活动，将肾神经切片，将切片神经的外周端放置在电极上，并记录肾传入神经的活动。 ...更多信息 n记录的电位。[结果与讨论] 1。肾传入神经刺激对血压的影响：以可变频率刺激肾传入神经20秒，以频率依赖性方式使WKY和SHR的血压下降。在高频（5-20 Hz）时，SHR和WKY的降压反应无显著差异，而在低频（1-2 Hz）时，SHR的降压反应明显小于WKY。在C4或T8脊髓切片后，这些降压反应完全消失，但在L2脊髓切片后没有消失。因此，SHR的这种反射可能是中枢性复位的。因此，肾传入细胞体可能位于T9-L2神经节。记录肾传入神经活动：由于静息传入神经放电非常低，因此难以与噪声区分。然而，神经放电显着增加，在肾静脉部分闭塞。输尿管压力的增加不影响神经放电。这些结果表明，肾组织压力的变化不刺激肾机械感受器，因此，机械感受器可能位于肾内静脉系统。肾静脉压升高使WKY和SHR的放电量增加程度相似。少

The kidney plays an important role in the regulation of systemic blood pressure via the metabolism of water and sodium, and via humoral factors such as the renin-angiotensin system. However, there is little information about the role of the renal afferent nerve. The present study was designed to clarify the role of the renal afferent nerve in the regulation of blood pressure, using Wistar-Kyoto rats (WKY) and spontaneously hypertensive rat (SHR).[Methods] Thirteen to 15-week-old WKY and SHR were used in this investigation. Under pentobarbital anesthesia, the left renal sympathetic nerves were exposed through a midline abdominal incision. Rectangular pulses were delivered to the renal nerve. The frequency was varied between 1 and 20 Hz, while the voltage and duration of stimulation were held constant (10 V and 1 msec, respectively). For recording of renal afferent nerve activity, the renal nerve was sectioned, the peripheral end of the sectioned nerve placed on electrodes, and the actio … More n potential recorded.[Results and Discussion] 1. Effects of renal afferent nerve stimulation on blood pressure: Renal afferent nerve stimulation at variable frequencies for 20 sec produced a fall in blood pressure in both WKY and SHR in a frequency-dependent fashion. At high frequencies (5-20 Hz) the depressor responses were not different between WKY and SHR, but at low frequencies (1-2 Hz) the responses were significantly smaller in SHR than in WKY. These depressor responses were completely abolished after spinal cord section at C4 or T8, but not after section at L2. It can be concluded that the reflex may be centrally reset in SHR. Thus, the renal afferent cell bodies may be located in the T9-L2 ganglion.2. Recording of renal afferent nerve activity: Since resting afferent nerve discharge is very low, it was difficult to distinguish from noise. However, nerve discharge was significantly increased during partial occlusion of the renal vein. An increase in ureteral pressure did not affect nerve discharge. These results indicate that the renal mechanoreceptor was not stimulated by these changes in renal tissue pressure, so the mechanoreceptor might be located in the intrarenal venous system. Elevation of renal venous pressure increased discharge to similar extent in both WKY and SHR. Less