Background It has been reported that the blood pressure high (BPH) mouse shows an increase in blood pressure and alterations in the brain catecholaminergic system as well as normal ventricular size. However, spontaneously hypertensive rats (SHR) show ventricular dilation, changes in CSF proteins and variations in the brain angiotensin-vasopressin system. The subcommissural organ (SCO), the organum vasculosum of the lamina terminalis (OVLT), the subfornical organ (SFO) and the area postrema (AP) are circumventricular organs (CVO) located in the third and fourth ventricle which are rich in neuropeptides such as angiotensin II and catecholamines Variations in the SCO have been reported in hydrocephalus and hypertension. The SFO has connections with the brain regions involved in the central regulation of blood pressure and cardiovascular function. The p73 isoforms function as essential pro-survival molecules in both the CNS and PNS and are important not just during the period of developmental death but also for the maintenance of at least some populations of adult neurons. In the absence of p73, ventricular enlargement occurs as neurons degenerate and tissue mass decreases, a phenomenon also observed in the degenerating human brain. The purpose of the present work is to study the TAp73 and ΔNp73 expression in neuroepithelial structures such us: the CVO and their variations in ventricular dilatation and arterial hypertension.