Nitric oxide synthase activity in genetic hypertension.

A porphyrinic sensor was used to monitor nitric oxide released from cultured endothelial and vascular smooth muscle cells obtained from genetically hypertensive rats and from a normotensive reference strain of rats. Endothelial cell nitric oxide synthase (the constitutive enzyme) was stimulated with bradykinin, and vascular smooth muscle cell nitric oxide synthase (the inducible enzyme) was induced with interleukin-1 beta. Both types of cells from hypertensive rats released less nitric oxide than did cells from normotensive rats. The observed deficient nitric oxide release from endothelial and smooth muscle cells may contribute to the elevated vascular tone and increased cell growth described in hypertension.