Nitric Oxide Synthase Inhibitor Blocks Spinal Sensitization Induced by Formalin Injection into the Rat Paw

Abstract

Fy the formalin response, the instances of “flinching behavior” were counted at 5-min intervals for 60 min. IT N-Arg depressed the flinching behavior in a dose-dependent manner when N-Arg was administered 10 min before the formalin injection. This N-Arg effect was reversed with L-arginine but not D-arginine. We conclude that NO plays an important role in nociceptive transmission in the spinal cord during the formalin test. Address correspondence and reprint requests to Tatsuo Yamamoto, MD, Department of Anesthesiology, School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260, Japan. Accepted for publication July 12, 1993. © 1993 International Anesthesia Research Society...