Development of the acoustic startle response in rats and its change after early acoustic trauma
Language English Country Netherlands Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
25746512
DOI
10.1016/j.bbr.2015.02.046
PII: S0166-4328(15)00135-7
Knihovny.cz E-resources
- Keywords
- Acoustic startle reflex, Auditory system, Critical period, Development, Noise exposure, Rat,
- MeSH
- Acoustic Stimulation adverse effects MeSH
- Cochlea cytology growth & development MeSH
- Rats, Long-Evans MeSH
- Sensory Thresholds physiology MeSH
- Auditory Perception physiology MeSH
- Evoked Potentials, Auditory, Brain Stem physiology MeSH
- Hearing Tests MeSH
- Synapses physiology MeSH
- Reflex, Startle physiology MeSH
- Animals MeSH
- Check Tag
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Even brief acoustic trauma during the critical period of development that results in no permanent hearing threshold shift may lead to altered auditory processing in adulthood. By monitoring the acoustic startle response (ASR), we examined the development of auditory function in control rats and in rats exposed to intense noise at the 14th postnatal day (P14). First ASRs appeared on P10-P11 to intense low-frequency tones. By P14, the range of sound intensities and frequencies eliciting ASRs extended considerably, the ASR reactivity being similar at all frequencies (4-32 kHz). During the subsequent two weeks, ASR amplitudes to low-frequency stimuli (4-8 kHz) increased, whereas the ASRs to high-frequency tones were maintained (16 kHz) or even decreased (32 kHz). Compared to controls, noise exposure on P14 (125 dB SPL for 8, 12, or 25 min) produced transient hyper-reactivity to startle stimuli, manifested by a decrease of ASR thresholds and an increase of ASR amplitudes. ASR enhancement occurred regardless of permanent hearing loss and was more pronounced at high frequencies. The hyper-reactivity of ASRs declined by P30; the ASR amplitudes in adult exposed rats were lower than in controls. The histological control did not reveal loss of hair cells in adult exposed rats, however, the number of inner hair cell ribbon synapses was significantly decreased, especially in the high-frequency part of the cochlea. The results indicate that early acoustic trauma may result in complex changes of ASRs during development.
References provided by Crossref.org
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