Immunoreactivity for calcium-binding proteins defines subregions of the vestibular nuclear complex of the cat

Abstract

The vestibular nuclear complex (VNC) is classically divided into four nuclei on the basis of cytoarchitectonics. However, anatomical data on the distribution of afferents to the VNC and the distribution of cells of origin of different efferent pathways suggest a more complex internal organization. Immunoreactivity for calcium-binding proteins has proven useful in many areas of the brain for revealing structure not visible with cell, fiber or Golgi stains. We have looked at the VNC of the cat using immunoreactivity for the calcium-binding proteins calbindin, calretinin and parvalbumin. Immunoreactivity for calretinin revealed a small, intensely stained region of cell bodies and processes just beneath the fourth ventricle in the medial vestibular nucleus. A presumably homologous region has been described in rodents. The calretinin-immunoreactive cells in this region were also immunoreactive for choline acetyltransferase. Evidence from other studies suggests that the calretinin region contributes to pathways involved in eye movement modulation but not generation. There were focal dense regions of fibers immunoreactive to calbindin in the medial and inferior nuclei, with an especially dense region of label at the border of the medial nucleus and the nucleus prepositus hypoglossi. There is anatomical evidence that suggests that the likely source of these calbindin-immunoreactive fibers is the flocculus of the cerebellum. The distribution of calbindin-immunoreactive fibers in the lateral and superior nuclei was much more uniform. Immunoreactivity to parvalbumin was widespread in fibers distributed throughout the VNC. The results suggest that neurochemical techniques may help to reveal the internal complexity in VNC organization.

Precerebellar and vestibular nuclei of the short-beaked echidna (Tachyglossus aculeatus)

“…With regard to calcium binding protein immunoreactivity, the echidna showed immunoreactivity in vestibular afferents for both PV and CB, similar to that seen in rodents (Kevetter 1996;Kevetter and Leonard 1997;Bä urle et al 1998). Immunoreactivity for PV appeared to be distributed widely throughout the neuropil of all the vestibular nuclei of the echidna, much like the pattern of neuropil immunoreactivity seen in the rodent vestibular complex (Baizer and Baker 2005;Paxinos et al 1999). As in rodents (Bä urle et al 1998;Paxinos et al 1999), immunoreactivity for CB was not uniformly distributed in all vestibular nuclei of the echidna, being strongest in SuVe, LVe and SpVe and weaker in MeVe.…”

Neurochemical and Structural Organization of the Principal Nucleus of the Inferior Olive in the Human

“…First, we have previously found that immunoreactivity to calcium-binding proteins and other markers could reveal subdivisions in brainstem structures of several species (Baizer and Baker, 2005;Baker, 2006a, 2006b;Baizer and Broussard, 2010); and we sought to determine whether the human IOpr might have similar subdivisions. This idea was prompted by the relationship of the IOpr with the cerebellar hemispheres and dentate nucleus, as functional and neurochemical subdivisions of the dentate nucleus have been found in primates (Dum et al, 2002).…”

Temporal Changes of the Calcium-binding Proteins in the Medial Vestibular Nucleus following Unilateral Labyrinthectomy in Rats

“…Vestibular nuclear complex showed a heterogenous distribution of calcium-binding proteins since the nucleus has a complex internal organization (Baizer & Baker, 2005). Histologically, the 8 th nerve is one source of immunoreactive fibers in the vestibular nuclei for calbindin and parvalbumin, but not calretinin.…”