Appearance of Glucocorticoid Receptors in the Inner Ear of the Mouse during Development

Abstract

CBA mice were sacrificed at different ages of developments at embryonic day 13 (E13), E14, E16, E19, E20 and postnatal day 1 (P1), P2, P3, P4, P6, P8, P10, P14, P16, P18, P20 and P30. The temporal bones were quickly removed and deep frozen in order to prepare cryosections for immunohistochemical staining with polyclonal antibodies against glucocorticoid receptors. The avidin-biotin, ABC-method was used to visualize binding. Both the vestibular and the cochlear regions of the inner ear were analysed. A faint staining of the crista ampullaris, the utricle and the cochlear duct was seen at E19; and staining became clearly visible at P1. A decrease in labelling was found at day 2-5 post partum whereafter an increased staining was again noticed until postnatal day 14 when an adult pattern was observed. The appearance of glucocorticoid receptors in the inner ear during development does not follow a linear curve. Further, the labelling pattern may indicate an impact of glucocorticoid receptors on the embryologic maturation itself as well as a functional role in the adult ear.

Long-term administration of magnesium after acoustic trauma caused by gunshot noise in guinea pigs

“…This glucocorticoid could use multiple transduction pathways, whether genomic or non-genomic (Makara and Haller, 2001). The presence of glucocorticoid receptors (GR) within the inner ear has been shown in rodents and humans (Ten Cate et al, 1993;Erichsen et al, 1996;Rarey and Curtis, 1996). The administration of RU486, a GR inhibitor, in noise-traumatised mice antagonized the protective effect of methylprednisolone (Hirose et al, 2007).…”

How Useful Is Corticosteroid Treatment in Cochlear Disorders?

“…Similarly, in guinea pigs the glucocorticoid receptor concentration in the lateral cochlear wall exceeded that in the ampulla of the semicircular canal [75]. The receptor expression during development in the rat [76] and in CBA mice [77] indicates a tissue-and age-specific nonlinear curve up to postnatal days 14-21, when an adult pattern was observed.…”

Blocking the Glucocorticoid Receptor with RU-486 Does Not Prevent Glucocorticoid Control of Autoimmune Mouse Hearing Loss

“…Toward this end, efforts have been made to better delineate the specific roles of the glucocorticoid and mineralocorticoid receptors in glucocorticoid treatments for hearing loss. Both mineralocorticoid [40,41] and glucocorticoid [42,43] receptors occur in the ear, and recent studies of cochlear pharmacokinetics of glucocorticoids have begun to clarify some parameters of steroid flow and scalar distribution, particularly after transtympanic delivery [44,45,46,47,48,49]. It is well established that glucocorticoids have an affinity for the mineralocorticoid receptor that is equal to or higher than affinity for the glucocorticoid receptor [50,51,52].…”