Synaptic Inhibition of Medial Olivocochlear Efferent Neurons by Neurons of the Medial Nucleus of the Trapezoid Body
| Autor: | Lester Torres Cadenas, Matthew J. Fischl, Catherine J.C. Weisz |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Cochlear Nucleus
Male 0301 basic medicine Patch-Clamp Techniques OHC Efferent Olivary Nucleus Biology Inhibitory postsynaptic potential Cochlear nucleus inhibitory synapse Mice 03 medical and health sciences Neurons Efferent 0302 clinical medicine Glutamates otorhinolaryngologic diseases medicine Animals Trapezoid body Auditory system auditory Axon medial olivocochlear Cochlear Nerve Research Articles Trapezoid Body General Neuroscience Excitatory Postsynaptic Potentials MNTB Axons Electric Stimulation Mice Inbred C57BL 030104 developmental biology medicine.anatomical_structure Acoustic Stimulation nervous system efferent Synapses Female sense organs Neuron Brainstem Neuroscience 030217 neurology & neurosurgery Cellular/Molecular Brain Stem |
| Zdroj: | The Journal of Neuroscience |
| ISSN: | 1529-2401 0270-6474 |
| Popis: | Medial olivocochlear (MOC) efferent neurons in the brainstem comprise the final stage of descending control of the mammalian peripheral auditory system through axon projections to the cochlea. MOC activity adjusts cochlear gain and frequency tuning, and protects the ear from acoustic trauma. The neuronal pathways that activate and modulate the MOC somata in the brainstem to drive these cochlear effects are poorly understood. Evidence suggests that MOC neurons are primarily excited by sound stimuli in a three-neuron activation loop from the auditory nerve via an intermediate neuron in the cochlear nucleus. Anatomical studies suggest that MOC neurons receive diverse synaptic inputs, but the functional effect of additional synaptic influences on MOC neuron responses is unknown. Here we use patch-clamp electrophysiological recordings from identified MOC neurons in brainstem slices from mice of either sex to demonstrate that in addition to excitatory glutamatergic synapses, MOC neurons receive inhibitory GABAergic and glycinergic synaptic inputs. These synapses are activated by electrical stimulation of axons near the medial nucleus of the trapezoid body (MNTB). Focal glutamate uncaging confirms MNTB neurons as a source of inhibitory synapses onto MOC neurons. MNTB neurons inhibit MOC action potentials, but this effect depresses with repeat activation. This work identifies a new pathway of connectivity between brainstem auditory neurons and indicates that MOC neurons are both excited and inhibited by sound stimuli received at the same ear. The pathway depression suggests that the effect of MNTB inhibition of MOC neurons diminishes over the course of a sustained sound.SIGNIFICANCE STATEMENTMedial olivocochlear (MOC) neurons are the final stage of descending control of the mammalian auditory system and exert influence on cochlear mechanics to modulate perception of acoustic stimuli. The brainstem pathways that drive MOC function are poorly understood. Here we show for the first time that MOC neurons are inhibited by neurons of the MNTB, which may suppress the effects of MOC activity on the cochlea. |
| Databáze: | OpenAIRE |
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