Mechanisms underlying the small intestinal fluid secretion caused by arachidonic acid, prostaglandin E1 and prostaglandin E2 in the rat in vivo

Mechanisms underlying the small intestinal fluid secretion caused by arachidonic acid, prostaglandin E1 and prostaglandin E2 in the rat in vivo. Acta Physiol Scand130, 633–442. Received 15 January 1987, accepted 27 February 1987. ISSN 0001–6772. Department of Physiology, University of Goteborg, Sweden. Prostanoids were given intraluminally (PGE2) or infused close intra-arterially (PGE1 and PGE2) or arachidonic acid was administered intraluminally to denervated jejunal segments of the rat in vivo. These experimental manoeuvres caused a net fluid secretion, although a 1000–fold higher concentration of the prostanoids was needed from the luminal than from the vascular side. I.v. hexamethonium or serosally applied lidocaine diminished the induced fluid secretion suggesting that the prostanoids act mainly by eliciting local secretory reflexes in the enteric nervous system. This nervously mediated secretion is not accompanied by any increase in tissue CAMP. However, at higher i.a. concentrations of PGE2 there seems to be a non-neurogenic effect on the enterocytes associated with an increase in tissue cAMP.