Hypergravity affects the developmental expression of voltage-gated sodium current in utricular hair cells.
We investigated, during the first postnatal week, a voltage-gated sodium current (INa) transiently expressed in neonatal utricular hair cells in rats raised in hypergravity. Its electrophysiological properties did not differ significantly from those recorded from rats raised in normal gravity, but a delay was observed in their developmental expression. In normal gravity conditions, INa expression is maximal at postnatal days 1-2, conferring on the hair cells the ability to fire action potentials, and is down-regulated during the first postnatal week, whereas in hypergravity conditions, the down-regulation is delayed by 4 days. This is the first demonstration showing that development under enhanced gravity affects the transient excitability phase that characterizes neonate utricular hair cells, by delaying a critical period of vestibular development.
Brugeaud
Aurore
A
I.N.S.E.R.M. U 583, Montpellier Institute for Neurosciences, Department of Pathophysiology and Therapy of the Inner Ear, Research Group on Vestibular Disorders, Hôpital St Eloi, Montpellier Cedex, France. abrugeaud@univ-montp2.fr
Gaboyard-Niay
Sophie
S
Puel
Jean-Luc
JL
Chabbert
Christian
C
D000818:Animals; D000831:Animals, Newborn; D004594:Electrophysiology; D005260:Female; D018471:Hypergravity / Q000009:adverse effects*; D015640:Ion Channel Gating; D018811:Maternal Exposure; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D017208:Rats, Wistar; D012444:Saccule and Utricle / Q000254:growth & development / Q000378:metabolism*; D015222:Sodium Channels / Q000096:biosynthesis* / Q000502:physiology
D015222:Sodium Channels