Considering this background and the fact that the role of CNP in the regulation of vascular tone in hypertensive states is unclear, we hypothesized that the impaired response of the NO system to CNP in SHR could affect vascular relaxation induced by the peptide in this model of hypertension but other endothelial systems or potassium channels could also contribute to this impaired response. Here, CNP is linked to hypertensive disorder.