Distribution of calcium-binding protein immunoreactivities in the guinea pig auditory brainstem

Abstract

This study was intended to provide an overview of the distribution of calcium-binding proteins in the rodent auditory brainstem. We based our observations on immunohistochemical material obtained in the guinea pig, a species widely used in auditory research in which a mapping of calcium-binding proteins in the auditory brainstem is still missing. Differences in the amounts of these proteins throughout the auditory brainstem were further analyzed semiquantitatively. Parvalbumin was present in most neurons and their axon terminals throughout the ascending auditory brainstem. Nuclei that surround the main relay nuclei of the ascending auditory pathway lacked labeling. Calretinin staining was prominent in spherical and globular cells of the cochlear nucleus, in their axon terminals in the superior olivary complex, and in principal cells of the medial superior olive. Measures of optical densities showed that auditory neurons involved in sound localization had the highest calretinin labeling levels. Calbindin D-28k was present in cartwheel cells of the dorsal cochlear nucleus, in almost all neurons of the medial nucleus of the trapezoid body, and in globular cells in the ventral nucleus of the lateral lemniscus. The labeling patterns for calretinin and calbindin D-28k were non-overlapping throughout the auditory brainstem. This was also evident in the ventral nucleus of the lateral lemniscus where calbindin D-28k-immunoreactive terminals were found in the medial portion, while the calretinin-immunoreactive terminals were observed in the lateral portion. This study presents the first direct and comprehensive comparison of these three calcium-binding proteins in the auditory brainstem of a rodent. Each antibody yields a unique staining pattern that provides a basis for further defining neuronal populations. In addition, since their axons are also selectively stained, auditory nuclei can further be compartmentalized based on different terminal fields. These immunoreactivities have provided clues to the complex structure of the auditory brainstem.

Medial Superior Olivary Neurons Receive Surprisingly Few Excitatory and Inhibitory Inputs with Balanced Strength and Short-Term Dynamics

“…As in other mammals, the major Ca 2ϩ binding protein in MSO neurons is parvalbumin (Vater and Braun, 1994;Caicedo et al, 1996;Lohmann and Friauf, 1996). We find inhibitory inputs are nearly exclusively parvalbuminergic and calbindinergic, whereas excitatory fibers express parvalbumin and calretinin.…”

Characterization of the rhesus monkey superior olivary complex by calcium binding proteins and synaptophysin

“…As previously pointed out , the observed CB-immunoreactivity seems to be a much more specific and common marker for MNTB, as seen in all mammalian species studied so far such as chinchilla (Kelley et al 1992), rat (Webster et al 1990;Friauf, 1993), Mongolian gerbil and grey short-tailed opossum (Bazwinsky, 1998;Bazwinsky et al 1999), guinea-pig (Caicedo et al 1996), bat (Zettel et al 1991) and cat (Adams & Mugnaini, 1990;Matsubara, 1990). CB-immunoreactivity of the rhesus monkey MNTB also included dendrites of neurons, which varied in their positions, as known from other mammals (Kuwabara & Zook, 1991;Banks & Smith, 1992).…”

Heterogeneous Calretinin Expression in the Avian Cochlear Nucleus Angularis

“…While calretinin was the only CaBP found in the chick auditory brain stem nuclei (Parks et al 1997;Rogers 1989a), three members of the CaBPs family, calretinin, parvalbumin, and calbindin, have been found in the mammalian auditory system (Bazwinsky et al 2005(Bazwinsky et al , 2008Braun et al 1991b;Braun and Piepenstock 1993;Caicedo et al 1996Caicedo et al , 1997Celio 1990;Förster and Illing 2000;Fredrich et al 2009;Friauf 1993Friauf , 1994Idrizbegovic et al 2001Idrizbegovic et al , 2004Idrizbegovic et al , 2006Kelley et al 1992;Kulesza 2014;Logerot et al 2011;Lohmann and Friauf 1996;Matsubara 1990;Vater and Braun 1994). These CaBPs formed complementary patterns of expression in the cochlear nuclei (Bazwinsky et al 2008;Fredrich et al 2009;Lohmann and Friauf 1996).…”