Spontaneous Cannabinoid Receptor 2 (CB2) Expression in the Cochlea of Adult Albino Rat and Its Up-Regulation after Cisplatin Treatment

PLoS One. 2016 Aug 26;11(8):e0161954. doi: 10.1371/journal.pone.0161954. eCollection 2016.

Abstract

We provide evidence for the presence of cannabinoid CB2 receptors in some cellular types of the cochlea of the adult albino rat. Cannabinoids and their receptors are increasingly being studied because of their high potential for clinical use. As a hyperspecialized portion of the peripheral nervous system, study of the expression and function of cannabinoid receptors in the hearing organ is of high interest. Stria vascularis and inner hair cells express CB2 receptor, as well as neurites and cell bodies of the spiral ganglion. Cellular types such as supporting cells and outer hair cells, in which the expression of other types of functional receptors has been reported, do not significantly express CB2 receptors in this study. An up-regulation of CB2 gene expression was detected after an ototoxic event such as cisplatin treatment, probably due to pro-inflammatory events triggered by the drug. That fact suggests promising potential of CB2 receptor as a therapeutic target for new treatments to palliate cisplatin-induced hearing loss and other ototoxic events which triggers inflammatory pathways.

MeSH terms

  • Animals
  • Cisplatin / pharmacology*
  • Cochlea / drug effects*
  • Cochlea / metabolism*
  • Ear, Inner / drug effects
  • Ear, Inner / metabolism*
  • Female
  • Fluorescent Antibody Technique
  • Immunohistochemistry
  • Rats
  • Rats, Wistar
  • Receptor, Cannabinoid, CB2 / genetics
  • Receptor, Cannabinoid, CB2 / metabolism*

Substances

  • Receptor, Cannabinoid, CB2
  • Cisplatin

Grants and funding

This work was supported by Instituto de Salud Carlos III PI 11/00742 (to RRC) http://www.isciii.es/, Plan Nacionall I+D+I 2008-2011 (to RRC) http://www.idi.mineco.gob.es/portal/site/MICINN/menuitem.7eeac5cd345b4f34f09dfd1001432ea0/?vgnextoid=fe5aec1eb658c310VgnVCM1000001d04140aRCRD, Fondo Europeo de Desarrollo Regional as a cofunder (to RRC) http://www.red.es/redes/%C2%BFquienes-somos/feder, Universidad Autónoma de Madrid (to RRC) http://www.uam.es/, Fundación Universidad Autónoma de Madrid SMS http://fuam.es/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.