The ependymocytes of the bovine subcommissural organ are functionally coupled through gap junctions

The subcommissural organ (SCO) is a circunventricular organ secreting glyco proteins into the ventricle. It is richly innervated by (1) serotonergic fi bers originated in raphe nuclei, that would exert an inhibitory control, an d (2) peptidergic fibers of unknown function. Due to the scarce number of t he latter, their functional significance might largely depends on whether t he cells of the SCO are functionally coupled through gap junctions. This in vestigation was designed to answer this question. The bovine SCO, either fr eshly isolated or maintained in organ culture, was processed for immunoblot and immunocytochemistry, using an anti-connexin43 antibody, and dye coupli ng studies. It was found that the cells of the SCO in situ are functionally coupled through gap junctions made at least of connexin43, but in cultured explants are not. The possibility that coupling of the SCO may be controll ed by the neural input and undergoes circadian variations is discussed. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.