Developmental expression of Ca(v)1.3 (alpha1d) calcium channels in the mouse inner ear.

1. Brain Res Dev Brain Res. 2004 Jun 21;150(2):167-75.

Developmental expression of Ca(v)1.3 (alpha1d) calcium channels in the mouse
inner ear.

Hafidi A(1), Dulon D.

Author information:
(1)Laboratoire de Biologie Cellulaire de l’Audition, EA3665 Université Victor
Segalen Bordeaux 2, Hôpital Pellegrin, PQR3, INSERM EMI 99-27, 33076 Bordeaux,
France.

Erratum in
Brain Res Dev Brain Res. 2004 Oct 15;153(1):151.

Voltage-gated calcium channels are important for neurotransmission at the level
of inner hair cells (IHCs) and outer hair cells (OHCs). These channels open when
mechanical stimulation depolarises the hair cell membrane and the resulting
calcium influx triggers neurotransmitter release. Voltage-gated calcium channels
expressed in hair cells are known to be of the L-type with a predominance of the
Ca(v)1.3 subunit. The present study describes the developmental expression of the
Ca(v)1.3 protein in the cochlea and the vestibular system using
immunohistochemical technique. In the adult organ of Corti (OC), Ca(v)1.3 was
localized in both sensory and non-sensory cells with a more intense expression in
IHCs and Deiters cells when compared to OHCs. In both hair cell types,
immunoreactivity was observed in the apical pole, basolateral membrane and at the
basal pole (synaptic zone). Similar results were obtained in the vestibular
organs. During development, Ca(v)1.3 immunoreactivity was observed in the cochlea
as early as embryonic day 15, with expression increasing at birth. At these early
stages of cochlear development, Ca(v)1.3 was expressed in all cell types
surrounding the scala media. In the OC, the labeling was observed in IHCs, OHCs
and supporting cells. The Ca(v)1.3 expression reached an adult-like pattern by
the end of the second postnatal week. The present findings suggested that, in
addition to their implication in hair cells synaptic transmission, Ca(v)1.3
calcium channels also play an important role in vesicle recycling and transport,
as suggested by their extrasynaptic location at the apical pole of the hair
cells. The Ca(v)1.3 channels in Deiters cells could participate in active
calcium-induced changes in micromechanics of these supporting cells. An early
expression during development suggested that these calcium channels are in
addition important in the development of the cochlear and vestibular sensory
epithelium.

DOI: 10.1016/j.devbrainres.2004.03.007
PMID: 15158080 [Indexed for MEDLINE]

Auteurs Bordeaux Neurocampus