CHANGES IN THE SECRETORY ACTIVITY OF THE SUBCOMMISSURAL ORGAN OF SPONTANEOUSLY HYPERTENSIVE RATS

The subcommissural organ (SCO) is a glandular circumventricular organ secreting glycoproteins into the cerebrospinal fluid. The SCO of 15-we ek-old spontaneously hypertensive rats (SHR) and of matched normotensi ve Wistar-Kyoto rats (WKY) was studied immunocytochemically by using a n antibody against the glycoproteins secreted by the SCO. The blood pr essure, water intake and volume of brain ventricles of SHR and WKY rat s were also recorded. The SHR were hypertensive, drank more water and did not display dilatation of the brain ventricles. The SCO of the SHR rats showed a drastic decrease of the immunoreactive material stored in the rough endoplasmic reticulum whereas the amount of immunoreactiv e apical secretory granules did not vary with respect to the SCO of WK Y rats. These changes are compatible with an increased secretory activ ity of the SCO of the SHR rats. It is suggested that the changes in th e SCO of SHR rats, and their hypertensive state, are interrelated phen omena. (C) 1998 Elsevier Science Ireland Ltd.