Figure 4.

Summary of vasorelaxation responses of isolated rat superior mesenteric artery rings (SMA). Vasodilation was measured in response to the highest concentration of vasodilators: 100 nM ACh, 1 μM A23187, and 100 μM NaNO₂. Trauma resulted in a significant retardation of relaxation to endothelium-dependent vasodilators (i.e., ACh and A23187) (P<0.01) but not to the endothelium-independent vasodilator (NaNO₂). There was no significant dysfunction in the vascular smooth muscle of the SMA in any of the Sham trauma or trauma groups since the responses to NaNO₂ were all normal. Traumatized rats treated with 125 μg kg⁻¹ VEGF 18 h pre-trauma did not develop endothelial dysfunction. Bar heights are the means; brackets indicate ±s.e.mean. The numbers in the parenthesis indicate the number of rings prepared from each experimental group.