Roman R J, Lechene C
Am J Physiol. 1981 May;240(5):F423-9. doi: 10.1152/ajprenal.1981.240.5.F423.
The recent finding that inhibitors of prostaglandin synthesis prevent the fall in urine concentration produced by papillary exposure challenges the hypothesis that contact between the pelvic urine and papilla is essential to the renal concentrating process. The present study examines the change in urine osmolality produced by exposure of the renal papilla in rats given meclofenamate. In control animals urine osmolality(Uosmol) decreased 57% after 2 h of exposure of the renal papilla. In rats given meclofenamate 4 mg/kg urine osmolality increased 16%, urine flow decreased 30%, and glomerular filtration rate was unchanged in the nonexposed kidney. Meclofenamate, however, did not alter the decrease in Uosmol seen in the kidney with the exposed papilla. Meclofenamate 10 mg/kg was also ineffective in preventing the fall in urine osmolality produced by papillary exposure, although this higher dose decreased glomerular filtration rate and arterial blood pressure. These results are consistent with the finding that pelvic urine urea is important to the urinary concentrating process and with the hypothesis that urine osmolality falls after papillary exposure because contact between pelvic urine and papilla is interrupted.
近期发现前列腺素合成抑制剂可阻止乳头暴露所导致的尿浓缩能力下降，这对肾盂尿液与乳头之间的接触对于肾脏浓缩过程至关重要这一假说提出了挑战。本研究检测了给予甲氯芬那酸的大鼠肾乳头暴露后尿渗透压的变化。在对照动物中，肾乳头暴露2小时后尿渗透压（Uosmol）下降了57%。在给予4mg/kg甲氯芬那酸的大鼠中，尿渗透压升高了16%，尿流量下降了30%，未暴露肾脏的肾小球滤过率未改变。然而，甲氯芬那酸并未改变暴露乳头的肾脏中Uosmol的下降情况。10mg/kg的甲氯芬那酸在预防乳头暴露所致的尿渗透压下降方面也无效，尽管该较高剂量降低了肾小球滤过率和动脉血压。这些结果与肾盂尿液尿素对尿液浓缩过程很重要这一发现一致，也与乳头暴露后尿渗透压下降是因为肾盂尿液与乳头之间的接触被中断这一假说相符。
