Role of nitric oxide in the control of burn perfusion

Vascular changes following deep skin burns are characterised by vasoconstri ction and progressive ischemia, Nitric oxide (NO) has been shown to be a po tent regulator of vascular smooth muscle tone and tissue perfusion. We asse ssed the importance of NO on post-burn skin perfusion in rats using laser D oppler. The present results show that neither the NO-synthase inhibitor, NG -nitro-L-arginine (L-NNA) (n = 6) nor the NO precursor, L-arginine, signifi cantly influenced skin perfusion in nonburned skin compared to saline-treat ed animals. In the area of full-thickness skin burn, neither L-arginine (Iz = 6) nor L-NNA (n = 6) had significant influence on post-burn perfusion co mpared to saline-treated controls (n = 6). Administration of L-NNA (n = 6) significantly impaired skin perfusion in the area adjacent to the contact b urn representing a partial-thickness burn, while the NO precursor, L-argini ne (n = 6) had no significant effect on burn perfusion as compared to salin e-treated controls (n = 6). In conclusion, impairment of perfusion in a ful l thickness burn following administration of NO-synthase inhibitor suggests that nitric oxide is involved in the mechanisms responsible for maintainin g adequate circulation post-burn. The lack of additional improvement of per fusion in response to L-arginine may suggest that NO synthesis in response to the thermal trauma is already at a peak. (C) 2000 Elsevier Science Ltd a nd ISBI. All rights reserved.