Research paperGlucocorticoid receptors modulate auditory sensitivity to acoustic trauma
Section snippets
Glucocorticoid history
The Nobel Prize in Medicine or Physiology was awarded in 1950 to Philip Hench, Edward Kendall and Tadeus Richtenstein for their work on the identification, characterization, and therapeutic use of hormones of the adrenal cortex, their structure and biological effects. They also studied the biological influence of the synthetic glucocorticoids, prednisone and dexamethasone. Since then, chronic glucocorticoid treatment has been found to be accompanied by serious side-effects, a finding that
Glucocorticoid receptors
Glucocorticoids are small lipophilic compound that are synthesized from cholesterol in the adrenal cortex by cytochrome P450-catalyzed reactions (Aron et al., 2004). Glucocorticoids affect organ development, tissue maturation, wound healing, and they are highly important in the modulation of inflammatory and immune responses (Smoak and Cidlowski, 2004). Glucocorticoids have an effect in almost all organs in the body and sensitivity to them depends on several factors including the availability
Glucocorticoid receptors in the inner ear
GR are expressed almost in all tissues but its concentration varies. GR have been detected in various parts of inner ear in humans and experimental animals (Rarey and Curtis, 1996, Shimazaki et al., 2002, Tahera et al., 2006, ten Cate et al., 1992). In the inner ear GR are localized to both neuronal and non-neuronal tissues and are modulated by acoustic trauma (Rarey et al., 1995, Terunuma et al., 2001, Tahera et al., 2006) or restraint stress (Curtis and Rarey, 1995). The glucocorticoid
Conclusions
The cellular levels of steroid hormone receptors fluctuate in response to stress depending on the individuals’ physiological and endocrine status. Responses of the HPA axis to acoustic stress are regulated by the cellular sensitivity to steroids, which is under control of the receptor availability and expression. It is known that long-term activation of glucocorticoid receptors can be detrimental to the central nervous system, while short-term activation can be advantageous. This review has
Acknowledgements
Supported by grants from the Swedish Research Council, AMF Trygghetsförsäkring, Tysta Skolan, Royal National Institute for Deaf People, and the Karolinska Institute.
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