Shear stress-induced nitric oxide antagonizes adenosine effects on intestinal metabolism
Han, C.; Ming, Z.; Lautt, W.W.
American Journal of Physiology 276(5): G1227-G1234
1999
ISSN/ISBN: 0002-9513 PMID: 10330014 Document Number: 501409
The influence of nitric oxide (NO) on adenosine-induced metabolic effects was studied in the intestine. Blood flow supplied an in situ-isolated segment of small intestine in anesthetized cats via the superior mesenteric artery (SMA) and was controlled by a vascular circuit. The SMA and portal samples were taken for analysis of oxygen and lactate. Adenosine (0.4 mg kg-1 min-1, intra-SMA) reduced oxygen consumption by 25.1 ± 2.9 from 73.1 ± 10.8 mmol min-1 100 g-1 and increased lactate production by 13.3 ± 3.0 from 12.8 ± 4.6 mmol min-1 100 g tissue-1 during constant-flow (CF, decreased shear stress) but not during constant-pressure (CP, increased shear stress) perfusion. Blockade of NO synthase using Nq-nitro- L-arginine methyl ester did not affect the metabolic effects of adenosine during CF but eliminated the differences seen between CP and CF perfusion. A NO donor, 3-morpholinosydnonimine, attenuated the metabolic effects of adenosine during CF perfusion. The results suggested that shear-induced NO antagonized metabolic effects of adenosine but that the inhibition of vascular effects by NO was not shear dependent since it occurred in both CP and CF perfusion. Reprinted by permission of the publisher.