Endolymphatic Potential Measured From Developing and Adult Mouse Inner Ear.
Level 5 - mechanism / opinion, no new human data
Animal physiological study (Level 5 by CEBM rules)
PubMed 33364922 · doi:10.3389/fncel.2020.584928
What was done
Electrophysiological measurements of endolymphatic potential (ELP) were recorded across inner ear compartments (basal and apical cochlear turns, saccule, utricle, and semicircular canals) in neonatal and adult C57BL/6J mice. Vestibular microphonic responses were also measured from neonatal saccules to assess functional maturation timing.
What was found
Adult mouse ELP differed across inner ear compartments: +95 mV in the basal cochlear turn, +87 mV in the apical cochlear turn, +9 mV in the saccule and utricle, and +3 mV in the semicircular canal. Vestibular ELP reached adult-like magnitude around postnatal day 6, approximately 12 days earlier than the maturation of cochlear ELP, coinciding with the maturation of saccular macular microphonic responses.
Why it matters
The study shows that endolymphatic potential operates as a localized potential across compartments despite similar fluid composition, and establishes that vestibular electrophysiological maturation precedes auditory maturation in mice.
Limits
The study was conducted entirely in C57BL/6J mice, which limits direct extrapolation to human development. Sample size (n), variability estimates (such as standard deviations), and statistical significance values were not reported in the abstract.
Cited by
- supports Georg von Békésy was the first to measure the endocochlear potential, a positive extracellular potential of approximately +100 millivolts in the inner ear, winning a Nobel Prize.