The Role of Nitric Oxide in Inflammation

Publisher Summary This chapter examines the multiple roles that nitric oxide (NO) may play during the inflammatory response. The majority of data implicating a role for NO in inflammation is based on experiments using nitric oxide synthase inhibitors. Inflammation results from increases in vascular flow, alterations in endothelium that can lead to plasma protein and leukocyte extravasation, and finally, the emigration of leukocytes from the circulation to the site of injury with resultant activation of effector cell mechanisms. There is evidence that NO can play a role during each stage of inflammation; the chapter discusses NO in the context of each of these stages. Conflicting data exist in the literature regarding the role of NO during inflammation. Some conflicts arise because of differences in the experimental systems studied such as in the animal species used or in the type of inflammatory stimulus. However, other differences may represent distinct physiologic and pathologic effects of NO during different phases of inflammation. NO plays a multifaceted role in all phases of the inflammatory immune response depending on the source and quantity of NO produced. It is important in the development of therapeutic modalities based on NO biochemistry and biology to take all roles of NO into consideration when designing potential treatments.