Ionic mechanism of the efferent olivo-cochlear inhibition studied by cochlear perfusion in the cat.

摘要: 1. A method for perfusing the scala tympani of cat's cochlea from basal turn to apex is described. The perfusion with modified Krebs solution did not interfere recording cochlear microphonic (CM) and neural responses sound, nor efferent inhibition elicited by stereotaxic stimulation crossed olivo-cochlear bundle (COCB) in medulla. 2. Cochlear solutions which most chloride was replaced large anions (sulphate or gluconate) decreased eliminated auditory nerve ventral nucleus. These effects were reversible. They only observed if rate (2-20 mul/min) adequate reduce concentration perilymph below about 80 mM, this being estimated, different same cochlea, a chloride-selective electrode. 3. COCB-induced negative shift endocochlear potential recorded glass micro-electrode inserted into media abolished I.V. strychnine o.2 mg/kg. It when reduced 50-70 mM could be dropped 5 mM. 4. potentiation also substitution but pattern effect differed that inhibition. 5. Similar perfusions small diameter bromide anion substituted affect COCB-efferent effects. 6. data indicate inhibitory transmitter released COCB terminals elicits an increased conductance (normally chloride) membrane dendrite outer hair cell. significance CM discussed, as well pre- post-synaptic mechanisms involved gating exerted on input. latter would seem involve primarily mechanism at axo-dendritic synapses.