Stimulation of intestinal mucosal afferent nerves increases superior mesenteric artery and decreases mesenteric adipose tissue blood flow

We tested the hypothesis that stimulation of intestinal mucosal afferent ne rves produces an increase in superior mesenteric artery (SMA) but a decreas e in mesenteric adipose tissue (MAT) blood flow. In anesthetized rats, bloo d flow in the SMA (pulsed Doppler flowmetry) and MAT (hydrogen gas clearanc e) was measured simultaneously before and after administration of 0.9% sali ne, 640 muM capsaicin, or 5% dextrose into the intestinal lumen. The change s in the SMA were 3.8 +/- 3.0, 15.9 +/- 4.0, and 18.8 +/- 7.6%; and those i n the MAT, 4.7 +/- 4.0, -11.5 +/- 3.4, and -0.07 +/- 3.4% of baseline, resp ectively. The data indicate that exposure of the intestinal lumen to an aff erent nerve stimulant or nutrient induced a dichotomous pattern of blood fl ow changes, an increase in the SMA and a reduction in MAT. The capsaicin-se nsitive afferent nerves may be instrumental in mediating these energy respo nses.