Abstract
It has been reported that spontaneously hypertensive rats (SHR) show ventricular dilation, changes in CSF proteins and variations in the circumventricular organs (CVO) such as: the subcommissural organ (SCO), the subfornical organ (SFO) and the area postrema (AP) which are located in the walls of the third and fourth ventricles. On the other hand, p73 proteins are present in cells of the central nervous system (CNS) such as circumventricular structures and the neuroepithelium which are altered in ventricular dilation. The purpose of the present work is to study the TAp73 isoform expression in the circumventricular organs (CVO) and their variations in ventricular dilatation and arterial hypertension. Brains and cerebrospinal fluid (CSF) from control Wistar-Kyoto rats (WKY) and SHR were used. The paraffin sections containing the CVO were immunohistochemically proc-essed with anti-TAp73 and by western blot, p73 bands in the CSF and circumventricular organ extract were also identified. The western blot study showed bands marked with p73 in the CSF and CVO, the p73 band expression was bigger in the SHR than in the WKY rats. We also found stronger markings in the SFO, SCO and AP of the hypertensive rats than in the WKY rats. It could be concluded that hypertension in the SHR produces altera-tions in the relationship between the p73 protein, circumventricular structures and CSF.
Highlights
Ritter and Dinh [1] described that spontaneously hypertensive rats present a progressive increase in ventricular size from 4 to 56 weeks of age, and in some SHRs ventricle size increased to 270% of control and such ventricular dilation could be produced by a loss of grey and white matter similar to what occurs in hydrocephalus, for this reason, certain systemic and behavioural signs which are concomitant with hypertension in the SHR may be attributable to hydrocephalus and its neuropathological correlates [1]
The expression of the transactivating isoforms of p73 (TAp73) in the subcommissural organ (SCO) of Wistar-Kyoto rats (WKY) rats was present in apical perinuclear parts of ependymal and hypendymal cells and some marks were even observed in the ventricle (Figures 1(A), (C); 2(I), (J))
Pozniak et al [20], indicating that p73 isoforms in the CNS are necessary for maintaining, at least, some populations of adult brain cells, a balance in p73 isoforms is necessary for maintaining normal central nervous system development, a balance which could be altered in the SHR
Summary
Ritter and Dinh [1] described that spontaneously hypertensive rats present a progressive increase in ventricular size from 4 to 56 weeks of age, and in some SHRs ventricle size increased to 270% of control and such ventricular dilation could be produced by a loss of grey and white matter similar to what occurs in hydrocephalus, for this reason, certain systemic and behavioural signs which are concomitant with hypertension in the SHR may be attributable to hydrocephalus and its neuropathological correlates [1]. Alterations in the secretions of cerebrospinal fluid proteins from the SCO have been described in spontaneously hypertensive rats [6]
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