Localization of the e-NOS enzyme in endothelial cells and odontoblasts of healthy human dental pulp

Nitric oxide synthases (NOS) are important enzymes present in different cel ls such as endothelial cells,;macrophages, etc. Recently, it has been found that nitric oxide (NO) is responsible for vasodilation, blood pressure reg ulation, platelet aggregation, cardiac contractility, and the mediation of immunity during bacterial infections and inflammation. However, the product ion and role of NO in various structures of the oral cavity have not been i nvestigated extensively. The aim of this study was to evaluate the presence of e-NOS in healthy human odontoblasts and endothelial cells of the dental pub. Twenty healthy human dental pulps were collected and frozen and pulp slices were obtained using a cryostat. The e-NOS enzyme was revealed by imm unohistochemical analysis and the enzyme level was detected by Western blot ting and mRNA expression by RT-PCR. The immunohistochemical results demonst rated, for the first time, the presence of e-NOS in odontoblasts and in end othelial cells. The presence of e-NOS m-RNA was confirmed by RT-PCR and the expression of the protein by Western blotting. These results clearly show that the e-NOS enzyme is present in both odontoblasts and endothelial cells of healthy human pulp. The presence of e-NOS in the odontoblast and endoth elial cells of the dental pulp may mediate local vasodilation and cell prol iferation. (C) 2000 Elsevier Science Inc. All rights reserved.