Immunocytochemical and stereological study of glucocorticoid receptors in rat medial vestibular nucleus neurons and the effects of unilateral vestibular deafferentation.
CONCLUSIONS
The results of this study suggest that neither the number of medial vestibular nucleus (MVN) neurons expressing cytosolic glucocorticoid receptors nor blood corticosterone levels change significantly during the development of vestibular compensation.


OBJECTIVE
Vestibular compensation is a process of partial behavioral recovery that occurs following damage to the vestibular labyrinth. It has been suggested that this compensation process might be dependent on the release of glucocorticoids such as corticosterone at the time of unilateral vestibular deafferentation (UVD) and that changes in glucocorticoid receptors in the MVN might contribute to the initiation of the compensation process.


METHODS
We compared the number of MVN neurons expressing cytosolic glucocorticoid receptors in rats at 10 h and 2 weeks following UVD, and in sham and anesthetic control animals; we also measured blood corticosterone levels.


RESULTS
Using immunocytochemistry and stereology, we found that the majority of MVN neurons expressed glucocorticoid receptors, but there were no significant differences in the number of glucocorticoid receptor-expressing neurons in the ipsilateral or contralateral MVNs at 10 h or 2 weeks post-UVD; furthermore, corticosterone levels did not vary significantly between the UVD and control groups.
Zhang
Rong
R
Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago Medical School, Dunedin, New Zealand.
Smith
Paul F
PF
Darlington
Cynthia L
CL
D000222:Adaptation, Physiological; D000704:Analysis of Variance; D000818:Animals; D003714:Denervation; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology; D011336:Probability; D051381:Rats; D017208:Rats, Wistar; D011987:Receptors, Steroid / Q000378:metabolism*; D012680:Sensitivity and Specificity; D014726:Vestibular Nuclei / Q000378:metabolism* / Q000473:pathology; D014722:Vestibule, Labyrinth / Q000294:innervation / Q000502:physiology*
D011987:Receptors, Steroid