AJP - Gastrointestinal and Liver Physiology, Vol 258, Issue 3 370-G376, Copyright © 1990 by American Physiological Society
Jejunal adenosine increases during food-induced jejunal hyperemia
D. R. Sawmiller and C. C. Chou
Department of Physiology, Michigan State University, East Lansing 48824-1101.
If adenosine mediates postprandial intestinal hyperemia, increases in local
adenosine release must accompany the hyperemia. We tested this by
determining jejunal venous and arterial plasma adenosine concentrations,
jejunal blood flow, and oxygen consumption before and during placement of
normal saline or predigested food plus bile into the jejunal lumen of
anesthetized dogs. Adenosine concentrations were measured by high-pressure
liquid chromatography. Luminal placement of food significantly increased
blood flow (+46%), oxygen consumption (+40%), venous adenosine
concentration (+56 nM), and adenosine release (+1.7 nmol.min-1.100 g
tissue-1) during the initial 3 min of placement. Whereas blood flow and
oxygen consumption remained elevated for the entire 15-min placement
period, venous adenosine concentration and release returned to control
levels at 7 and 11 min after placement, respectively. Placement of the same
volume of normal saline did not significantly alter any variables measured,
indicating that the food-induced changes were because of constituents of
food. In conclusion, introduction of predigested food into the jejunal
lumen significantly increases adenosine releases into the local venous
blood during the initial several minutes of food placement. The increased
adenosine production and release may play a role in postprandial jejunal
hyperemia.
