Depressed sensitivity of the hepatoportal NaCl receptors in rats with carbon tetrachloride-induced liver cirrhosis

K. Tanaka, T. Matsuda, H. Morita and H. Hosomi Department of Physiology, Kagawa Medical School, Japan. In normal rats, the activity of the hepatoportal NaCl-sensitive afferent nerves is increased by portal injection of hypertonic NaCl. In the present article, we have found this effect to be markedly reduced in rats with CCl4-induced liver cirrhosis (CT rats). Liver tissue norepinephrine content, a marker of tissue innervation, was also decreased in the treated rats. Over the 12 wk CCl4-treatment period, no significant difference in Na balance was found between control and CT rats when both groups were given normal NaCl (0.45%) food. However, when both were given high NaCl (8%) food, the Na balance of CT rats was positive and greater than that of controls. These results indicate that the sensitivity of the hepatoportal NaCl receptors is decreased even when the degree of liver cirrhosis is slight. This mechanism plays an important role in maintaining Na balance during intake of high NaCl food.