Loss of basic fibroblast growth factor in the subcommissural organ of old spontaneously hypertensive rats

The immunocytochemical localization of basic fibroblast growth factor (bFGF) was studied in subcommissural organ (SCO) of aged-matched normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SH) rats at 10, 14 and 18 months of age using a polyclonal antibody against bFGF. The bFGF-like immunoreactivity (bFGF-ir) was observed in SCO ependymal cells of young and old normotensive rats. However, a progressive loss of bFGF-immunopositive ependymal SCO cells was observed with age in SH rats (27.24, 57.5 and 96.9% in 10, 14 and 18 months old respectively) compared with aged-matched WKY normotensive rats. Considering the potential role of the SCO in sleep regulation and sodium homeostasis, which are altered in essential hypertension, these data show a new neuroendocrine anomaly to be added to the many others previously observed in this rat strain, when they develop hypertension as they get old.