Morita H, Matsuda T, Furuya F, Khanchowdhury M R, Hosomi H
Department of Physiology, Kagawa Medical School, Japan.
Circ Res. 1993 Mar;72(3):552-9. doi: 10.1161/01.res.72.3.552.
Responses of renal nerve activity and urinary Na+ and Cl- excretion were examined in chronically instrumented conscious dogs through feedings of boiled rice with or without NaCl. The boiled rice (20 g/kg body wt) without NaCl did not influence plasma Na+ and Cl- concentrations, renal nerve activity, or urinary Na+ excretion but decreased urinary Cl- excretion. On the other hand, boiled rice containing NaCl (0.4 g/kg body wt) increased plasma Na+ (+3.8 +/- 0.7 meq/l) and Cl- (+3.0 +/- 1.5 meq/l) concentrations, then decreased renal nerve activity by 61 +/- 4%, and increased urinary Na+ and Cl- excretions. In dogs with hepatic denervation, a decrease in renal nerve activity, which was observed in intact dogs in response to the high-NaCl food intake, was completely abolished along with significant attenuation of postprandial natriuresis. That is, only 9 +/- 5% of the loaded Na+ and 7 +/- 3% of the loaded Cl- were excreted during 4 consecutive hours in hepatic-denervated dogs, whereas 36 +/- 5% of the loaded Na+ and 36 +/- 4% of the loaded Cl- were excreted in intact dogs. In dogs with renal denervation, postprandial natriuresis was also attenuated. These results indicate that the high-NaCl food intake elicits a decrease in renal nerve activity, the decrease is predominantly mediated by the hepatic nerves, and the decrease in renal nerve activity plays an important role in augmentation of urinary Na+ and Cl- excretion. Thus, the hepatorenal reflex may play an important role in controlling extracellular fluid homeostasis during food intake.
通过给长期植入仪器的清醒犬喂食含或不含氯化钠的米饭，研究了肾神经活动以及尿钠和氯排泄的反应。不含氯化钠的米饭（20克/千克体重）不影响血浆钠和氯浓度、肾神经活动或尿钠排泄，但会降低尿氯排泄。另一方面，含氯化钠的米饭（0.4克/千克体重）会使血浆钠浓度升高（+3.8±0.7毫当量/升）和氯浓度升高（+3.0±1.5毫当量/升），随后肾神经活动降低61±4%，并增加尿钠和氯排泄。在肝去神经支配的犬中，完整犬摄入高钠食物后观察到的肾神经活动降低完全消失，同时餐后利钠作用显著减弱。也就是说，肝去神经支配的犬在连续4小时内仅排出9±5%的摄入钠和7±3%的摄入氯，而完整犬则排出36±5%的摄入钠和36±4%的摄入氯。在肾去神经支配的犬中，餐后利钠作用也减弱。这些结果表明，摄入高钠食物会引起肾神经活动降低，这种降低主要由肝神经介导，且肾神经活动降低在增加尿钠和氯排泄中起重要作用。因此，肝肾反射可能在进食期间控制细胞外液稳态中起重要作用。
