Postnatal development of the auditory brainstem response (ABR) in beagles.
Postnatal development of the auditory brainstem response (ABR) in beagles was studied by repeated ABR recordings from birth to 16 weeks of age. In ABR recording, waves I, II and III appeared at the same time 13 to 17 days of age, while wave IV during 13 to 20 days of age and wave V during 20 to 35 days of age, respectively. The latencies of waves II, III and IV became close to the control level at 6 weeks of age, whereas wave I had a similar latency to the control at 3 weeks of age. The latency of wave V became close to the control level at 8 weeks of age. I-III interpeak latency stabilized at 4 weeks of age, however, I-V and III-V interpeak latencies stabilized during 8 to 10 weeks of age. There was a marked individual difference in amplitude of ABR components in beagles. Wave I amplitude reached the plateau level at 3 weeks of age, and wave II, III and IV at 6 weeks of age. No further development in ABR was observed on and after 10 weeks of age. It may be concluded, from electrophysiological point of view, that the peripheral auditory pathway matures at 3 weeks of age and the auditory rely system in brainstem at 10 weeks of age in beagles.
Kuse
H
H
Safety Research Laboratory, Tanabe Seiyaku Co. Ltd., Osaka, Japan.
Okaniwa
A
A
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001306:Auditory Pathways / Q000254:growth & development*; D001933:Brain Stem / Q000254:growth & development* / Q000502:physiology; D004285:Dogs; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D008297:Male