Electrophysiological monitoring of the cochlea during and after total destruction of the organ of corti.
A series of acoustically evoked potentials can be recorded from the cochlea up to the auditory cortex in guinea pigs where the organ of Corti has been totally destroyed after extensive treatment with amikacin, but where some of the spiral ganglion neurons always remain and where the vestibular receptors are only slightly affected. The cochlear responses have been monitored in guinea pigs permanently implanted with a round window electrode and receiving such treatment. The normal auditory nerve compound action potential disappears within a few days, while the very typical response (diphasic, short latency (0.3 ms) small amplitude) appears. This response then remains remarkably constant in time as far as we could observe (up to almost one year). This response might be a component of the normal response, undiscernible under normal conditions but revealed by the selective impairment of the labyrinth by amikacin, in contrast to the global effect of every other known otodestructive agent. Some basic questions still remain: which fibres are effectively stimulated (cochlear or vestibular), what are their central projections, and what kind of sensation is conceivably associated with these responses?
D000583:Amikacin / Q000633:toxicity*; D000818:Animals; D001303:Auditory Cortex / Q000503:physiopathology; D001309:Auditory Threshold; D003051:Cochlea / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D004566:Electrodes; D005072:Evoked Potentials, Auditory / Q000187:drug effects; D006168:Guinea Pigs; D007612:Kanamycin / Q000031:analogs & derivatives*; D008991:Monitoring, Physiologic; D009410:Nerve Degeneration; D009925:Organ of Corti / Q000187:drug effects*; D013136:Spiral Ganglion / Q000503:physiopathology; D013997:Time Factors; D000159:Vestibulocochlear Nerve / Q000503:physiopathology
D007612:Kanamycin; D000583:Amikacin