Cochlear microphonic changes after noise exposure and gentamicin administration during sleep and waking.
These experiments were designed to investigate the effect of noise, sleep, and gentamicin on the cochlear microphonic (CM) of the guinea pigs. Are the changes observed due to intrinsic cochlear phenomena or to efferent system actions? To answer this question, noise exposure together with efferent system blockade by gentamicin administration was performed. In the normal (non-treated) animal, noise exposure decreased both variability and amplitude of the tone evoked CM in about the first 10 min while the physiological modulation of slow wave sleep increasing the CM is not present. Following administration of gentamicin, noise no longer affect the CM in about the first 10 min, although it produces amplitude and variability increments. The influence of slow wave sleep on the CM is not altered. Thus, gentamicin does not block the CM sleep/wakefulness related shifts. The data were discussed in terms of the influence of gentamicin on the olivo-cochlear bundle. It was hypothesized that the effects of noise on the CM is a result of both peripheral and central influences.
Neurofisiología, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Av. Gral. Flores 2125, Montevideo 11800, Uruguay.
Marisa
M
Pedemonte
Daniel G
DG
Drexler
Ricardo A
RA
Velluti
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects*; D003055:Cochlear Microphonic Potentials / Q000187:drug effects / Q000502:physiology*; D004525:Efferent Pathways / Q000187:drug effects / Q000502:physiology; D005839:Gentamicins / Q000008:administration & dosage / Q000009:adverse effects*; D006168:Guinea Pigs; D009622:Noise / Q000009:adverse effects*; D012890:Sleep / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*
D000900:Anti-Bacterial Agents; D005839:Gentamicins