Sympathetico-adrenergic influences on the small intestinal vascular reactions in experimental septic shock

The objective of this study was to explore the vascular reactions in the small intestine and the possible role of sympathetico-adrenergic influences. The experiments were performed on 23 cats. The small intestinal blood flow was estimated using a drop counting technique. In one series of cats (n = 7) the small intestine and the adrenal glands had intact vascular and nervous supply (I), in another series (n = 7) the small intestine was sympathetically denervated and the adrenal vessels ligated (II), and in a third series (n = 9) the small intestine was innervated but the adrenal vessels ligated (III). The septic state was induced by i.v. infusion of live E. coli bacteria for two hours. The small intestinal blood flow decreased and intestinal blood flow resistance increased in all series within 3 min upon bacterial infusion. The intestinal vasoconstriction was maintained in cats with intestinal denervation as well as in cats with the adrenal vessels ligated, favouring that other humoral factors than catecholamines are involved. During the later phase of bacteremic shock the intestinal blood flow remained in the preseptic range in the series with a denervated small intestine and ligated adrenals as well as in intact cats, but declined gradually and significantly in cats with adrenal ligation only (III). This pattern of reactions favours a local rather than a remote sympathetico-adrenal influence.