[Physiological and pathological effects of nitric oxide and nitric oxide synthase in oral cavity].

Nitric oxide (NO) is a short-lived free radical which is not only involved in regulating many physiological processes of the body, but also closely related to many diseases. Nitric oxide synthase (NOS) is the key enzyme for NO production. NOS exists as three distinct isoforms, the endothelial NOS (eNOS), neuronal NOS (nNOS) and inducible NOS (iNOS). It has been found that nNOS and eNOS were expressed in normal pulp tissues, periodontal tissues and salivary glands, and the NO produced from nNOS and eNOS was involved in their physiological functions. NO and iNOS are involved in the occurrence and development of pulpitis, periodontitis, salivary gland disease and oral cancer. This review focuses on the physiological and pathological effects of NO and different subtypes of NOS in oral cavity.一氧化氮是一种半衰期较短的自由基，不仅参与调节机体的许多生理过程，而且与机体众多病理过程密切相关。一氧化氮合酶（nitric oxide synthase，NOS）是一氧化氮生成的关键酶，其有3种亚型分别为神经元型NOS（neuronal NOS，nNOS）、内皮型NOS（endothelium NOS，eNOS）和诱导型NOS（inducible NOS，iNOS）。研究发现nNOS和eNOS在正常的牙髓组织、牙周组织及唾液腺中均有表达，产生的一氧化氮参与其生理功能；而iNOS及产生的一氧化氮参与牙髓炎、牙周炎、唾液腺疾病和口腔癌等的发生发展。本文围绕一氧化氮及不同亚型NOS在口腔中的生理及病理作用进行综述。.