Differential effects of prenatal chronic high-decibel noise and music exposure on the excitatory and inhibitory synaptic components of the auditory cortex analog in developing chicks (Gallus gallus domesticus).
Proper development of the auditory cortex depends on early acoustic experience that modulates the balance between excitatory and inhibitory (E/I) circuits. In the present social and occupational environment exposure to chronic loud sound in the form of occupational or recreational noise, is becoming inevitable. This could especially disrupt the functional auditory cortex development leading to altered processing of complex sound and hearing impairment. Here we report the effects of prenatal chronic loud sound (110-dB sound pressure level (SPL)) exposure (rhythmic [music] and arrhythmic [noise] forms) on the molecular components involved in regulation of the E/I balance in the developing auditory cortex analog/Field L (AuL) in domestic chicks. Noise exposure at 110-dB SPL significantly enhanced the E/I ratio (increased expression of AMPA receptor GluR2 subunit and glutamate with decreased expression of GABA(A) receptor gamma 2 subunit and GABA), whereas loud music exposure maintained the E/I ratio. Expressions of markers of synaptogenesis, synaptic stability and plasticity i.e., synaptophysin, PSD-95 and gephyrin were reduced with noise but increased with music exposure. Thus our results showed differential effects of prenatal chronic loud noise and music exposures on the E/I balance and synaptic function and stability in the developing auditory cortex. Loud music exposure showed an overall enrichment effect whereas loud noise-induced significant alterations in E/I balance could later impact the auditory function and associated cognitive behavior.
Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
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V
Kumar
Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India. Electronic address: tapasnag@aiims.ac.in.
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TC
Nag
Department of NMR, All India Institute of Medical Sciences, New Delhi 110029, India.
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U
Sharma
Department of NMR, All India Institute of Medical Sciences, New Delhi 110029, India.
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NR
Jagannathan
Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India.
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S
Wadhwa
D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001303:Auditory Cortex; D030161:Avian Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002642:Chick Embryo; D002645:Chickens; D018698:Glutamic Acid / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D009146:Music; D009474:Neurons / Q000502:physiology; D009622:Noise / Q000009:adverse effects; D010507:Periodicity; D011312:Pressure; D016548:Prosencephalon / Q000196:embryology* / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D016708:Synaptophysin / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D030161:Avian Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; D016708:Synaptophysin; C073441:gephyrin; D001224:Aspartic Acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; C000179:N-acetylaspartate
GABA; PSD-95; avian; field L; gephyrin; glutamate