Postnatal development of vimentin‐positive cells in the rabbit superior colliculus

Abstract

The present study examined the postnatal development of the radial glia in the rabbit superior colliculus during the first 40 postnatal days. An antivimentin monoclonal antibody and the carbocyanine fluorescent tracer DiI were used in order to investigate the development of laminar connectivity in the superior colliculus. We focused our study on the superficial gray layer, the intermediate layer, and the deep layers of the superior colliculus, the periaqueductal gray matter (PAGM), and the medial intercollicular region. Vimentin-positive structures of glial lineage consisted of 1) the main radial system, which in the newborn rabbit was made up of wavy fibers that ran from the aqueduct to the pial surface, where they terminated in end-feet. At postnatal day 15, these fibers diminished to 100-200 microns long wavy tracts, which emanated from the aqueduct, and to a few straight or arched fragments in the superficial gray layer; 2) the median ventricular formation, which extends from mesencephalic aqueduct to the intercollicular sulcus, was characterized by a series of ascending, vimentin-positive fibers, some of large caliber, which persisted until postnatal day 40; 3) the tangential fiber system, which was made up of fibers that diverged from the median ventricular formation and of a number of short tracts running perpendicular to the periaqueductal radial fibers; these structures may provide support for migrating subpopulations of neurons; 4) immature and mature-like protoplasmic and fibrous astrocytes, which appeared during the second postnatal week. Thereafter, the number of vimentin-positive astrocytes decreased sharply. Our findings generally support earlier descriptions of the radial glia, except for the persistence, in superficial layers of the superior colliculus, of straight and curved fragments of fibers, which may participate in the organization of visual afferents at this level.

Vimentin-Immunoreactivity in the Developing Striatum of the Rat.

“…These morphological changes of vimentin-immunoreactivity are similar to those reported in the VZ of the cerebral cortex [3,8,25,29] and periaqueductal gray matter [26,34]. Previous immunohistochemical studies using other antibodies as a radial glial marker, such as RC1 and RC2 [7,10,20,21], have also reported similar sequential changes in radial glia.…”

“…In rodents, this transformational change is thought to be accompanied by an alteration of intermediate filament proteins, from vimentin to glial fibrillary acidic protein (GFAP) [5,12,25]. Examples of radial glial transformation outside the cerebral cortex have been reported in the superior colliculus [26,27], hypothalamus [8,31], brainstem [8] and cerebellum [30,35,36]. Using vimentin-immunohistochemistry, Pulido-Caballero et al [27] reported on the appearance of vimentin-positive rosary-bead-like fibers in the rabbit superior colliculus during the period of radial-glial transformation and proposed that the segmentation of vimentin-positive fibers was a novel form of radial glial transformation.…”

The Experimental Manipulation of Visual Cortex Efferents

“…These observations may explain the differences in axonal branching between deafferented neonates and adults. Indeed, we also found that immature vimentin-expressing astrocytes are abundant in the neonatal SC [47], where they may induce local sprouting after retinal deafferentation.…”

Glial fibrillary acidic protein and vimentin immunoreactivity of astroglial cells in the central nervous system of adult Podarcis sicula (Squamata, Lacertidae)

“…Even though vimentin has been found in immature cells of the astroglial lineage in mammals (Elmquist et al 1994 ;Pulido-Caballero et al 1994) and reptiles (Monzon-Mayor et al 1990 ;Yanes et al 1990), it is still present in adult glial cells in teleosts and amphibians (Zamora & Mutin, 1988 ;Cardone & Roots, 1990 ;Rubio et al 1992 ;Lazzari et al 1997). Furthermore, vimentin is highly conserved in phylogenesis as suggested by the cross reaction of antibodies produced against mammalian vimentin with the corresponding protein in birds and amphibians (Bennett et al 1978 ;Szaro & Gainer, 1988 ;Zamora & Mutin, 1988 ;Bodega et al 1994).…”