Early postnatal development of ependyma in the third ventricle of male and female rats

Abstract

Ependyma in the third ventricle of developing male and female rats (0, 5, and 10 days postpartum) were compared with those of sexually mature male rats by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). No sexual dimorphism appeared in the developmental group. At all ages the dorsolateral ventricular wall was composed of ciliated ependymal cells, while ependymal cells of the ventrolateral wall exhibited apical microvilli and bleb-like irregularities. While SEM revealed similarities in apical morphology between ependymal cells adult and developing animals, TEM revealed marked differences between these cells. Many ciliated ependymal cells in developing animals resembled those of the adult while other neonatal cell profiles suggested ciliogenesis. Adult male rats exhibited two distinct tanycyte populations. One population, characterized by elaborate intercellular interdigitations and basal processes containing predominantly fine filaments, occurred adjacent to the ventromedial nucleus (VMN). The second population, characterized by less extensive intercellular interdigitations and basal processes containing, primarily microtubules, lined the roof of the lateral recess adjacent to the arcuate nucleus. Many tanycytes at the level of the arcuate nucleus in developing rats resembled closely those of the adult. In contrast, developing ependymal cells at the level of the VMN differed differed from their adult counterparts in that they exhibited little intercellular interdigitation and projected basal processes characterized by an internal framework of microtubules. Similarities in cytology between developing and adult tanycytes of the arcuate region suggest that the adult function of this population may be operative in the early postnatal period. In contrast, the differing cytology between adult and developing tanycytes of the VMN region suggests that the function of these cells is age-dependent.

Developmental changes in hypothalamic leptin receptor: relationship with the postnatal leptin surge and energy balance neuropeptides in the postnatal rat

“…Injection of radiolabeled thymidine ( 3 H-thymidine) into pregnant rat dams identified that neurons of most hypothalamic nuclei originate between E14 and E18 within the ventricular zone of the hypothalamic third ventricle (6,7,10,20) and that these postmitotic neurons subsequently migrate laterally to populate the surrounding nuclei (10). Morphological changes similar to those reported here, in terms of ventricular thinning over the first postnatal weeks, have been reported previously (44) and suggested that this change may be the result of neuronal migration away from the ventricular zone. In addition, there appears to be a decline in the number of cells both within the ventricular region and also the surrounding ARC and VMH areas with increasing age.…”

Neuronal nitric oxide synthase immunoreactivity in ependymal cells during early postnatal development

“…It has been reported that in early postnatal period, developmental processes continue in ependymal cells of the third ventricle of the rat (Bruni, 1998;Walsh et al, 1978), the central canal of the mouse (Sturrock, 1981) and the lateral ventricle of the rabbit (Abbate et al, 1993). In cats ependyma forms the complete lining of the surface of the central canal until 2 or 3 months after birth in domestic cats (Bohme, 1988).…”

Localization of metallothionein in the brain of rat and mouse.

“…of the spinal cord, are very active in cell proliferation in fetal and newborn rat but not in adult rat (Bruni et al, 1985). These cells differentiate until a certain period after birth (Bruni et al, 1983;Roessmann et al, 1980;Walsh et al, 1978). For example, ependymal cells of rat brain show many mitotic figures until 10 days after birth (Walsh et al.…”