No abstract

The relaxant effect of capsaicin (300 nM) has been studied on mucosa-free circular strips of the human sigmoid colon in vitro. The response of precontracted preparations to capsaicin (sub-maximal relaxation) was reduced by over 50% by the nitric oxide synthase inhibitor N(G)-nitro- L-arginine (L-NOARG; 20 microM or 100 microM) or by the guanylate cyclase inhibitor 1 H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 1 microM), but not by tetrodotoxin (1 microM) or the P(2) purinoceptor antagonist pyridoxal phosphate 6-azophenyl-2',4'-disulfonic acid (PPADS; 50 microM). L-NOARG or ODQ caused moderate contraction of the circular muscle, indicating a tonic "nitrergic" control. Anandamide (1-100 microM), an endogenous cannabinoid and capsaicin VR(1) receptor stimulant, failed to either mimic or modify the response to capsaicin (300 nM). It is proposed that capsaicin causes the release of smooth muscle relaxant substance(s) from afferent nerve endings in the gut wall, in a tetrodotoxin-resistant manner. Nitric oxide (possibly released from capsaicin-sensitive afferents) plays an important role in the capsaicin-evoked response. No evidence has been found for an involvement of PPADS-sensitive P(2) purinoceptors in the response to capsaicin or for a stimulation or inhibition of capsaicin-sensitive receptors by anandamide in the human sigmoid colon.

No abstract

Three cases of stenosis of a Roux loop are presented, following the replacement of the lower third of the esophagus resected for cancer. In each case fibrotic stenosis developed 6 weeks after reconstruction, which was attributed to ischemia: in one case it was due to reduced blood flow during digitalization and in the other two cases to the vascular compression of the supplying vessels because of unsatisfactory dilatation of the hiatus.