[The effects of substance P antibody on tuning curve of auditory evoked potential of cochlear nucleus and inferior colliculus in guinea pigs].

OBJECTIVE

To explore the effects of substance P on the frequency analysis of sound signals in the auditory brainstem.

METHODS

The electrodes were implanted into the cochlear nucleus (CN) and the inferior colliculus (IC) of guinea pigs. The auditory evoked potential in CN (CN-AEP) and IC (IC-AEP) was recorded with tone pip stimulation and tone burst forward masking techniques. The Q10 dB values of the tuning curves were compared between the CN-AEP and IC-AEP after injection of SP antibody or rabbit serum with the same dosage (used as control) into the nucleus.

RESULTS

After injection of SP antibody, the Q10 dB values of the tuning curves of CN-AEP and IC-AEP had no significant changes in 1 kHz and 2 kHz probe tone groups. When probe tone frequencies were 4 kHz and 6 kHz, there was a significant difference between the two frequency groups in Q10 dB. In addition, the higher frequency slope and lower frequency slope value had corresponding changes.

CONCLUSION

The results imply that SP could act as a neuromediator in the auditory afferent system and participated in the high frequency analysis in the auditory brainstem.