Role of mesenteric lymphatic system in water absorption from rat intestine in vitro

¹ Department of Physiology, University of Minnesota, Minneapolis, Minnesota

With an in vitro rat jejunal preparation it was found that at low distention pressures the absorption rate of segments without mesentery are about 40% lower than the rate of those with intact mesentery. The decrease of absorption rate in segments with lacteal ducts sectioned near the gut wall was the same as the rate for those completely devoid of mesentery. Section of blood vessels showed no decrease but rather a slight increase in rate. The mesenteric lymphatic ducts during water absorption in vitro and in vivo showed rhythmical contractions with an average frequency of 10/min. The lymphatic ducts of an isolated mesentery may continue to contract and transport water for a few minutes. The lymphatic pressure of the isolated segment is assumed to be an approximate measure of absorbing force. Epinephrine may augment lymphatic contractility and may also elevate lymphatic pressure. These observations suggest that the mesenteric lymphatics may play a significant role in water transport.