Chemical inactivation of the nucleus tractus solitarius abolished hepatojejunal reflex in the rat.

Jejunal electrolyte absorption was measured in the jejunal loop of anesthetized rats during an infusion of 9% NaCl solution via the portal vein. Net absorption of Na and Cl, and osmolality were significantly depressed by the portal 9% NaCl infusion. The decrease in net absorption was completely abolished by hepatic denervation. In addition, bilateral chemical inactivation of the nucleus tractus solitarius (NTS) by microinjection of kainic acid abolished the depressing effect of the portal venous infusion of 9% NaCl. These findings indicate that NTS is involved in the central pathway of the hepatojejunal reflex.