Artículo
Mechanisms of synaptic depression at the hair cell ribbon synapse that support auditory nerve function
Fecha de publicación:
09/2017
Editorial:
National Academy of Sciences
Revista:
Proceedings of the National Academy of Sciences of The United States of America
ISSN:
0027-8424
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Inner hair cells (IHCs) in the cochlea are the mammalian phono-receptors, transducing sound energy into graded changes in membrane potentials, the so called “receptor potentials.” Ribbon synapses between IHCs and auditory nerve neurons are responsible for converting receptor potentials into spike rates. The characteristics of auditory nerve responses to sound have been described extensively. For instance, persistent acoustic stimulation produces sensory adaptation, which is revealed as a reduction in neuronal spike rate with time constants in the range of milliseconds to seconds. Since the amplitude of IHC receptor potentials is invariant during this period, the classic hypothesis pointed to vesicle depletion at the IHC as responsible for auditory adaptation. In this study, we observed that fast synaptic depression occurred in responses to stimuli of varying intensities. Nevertheless, release continued after this initial depression, via synaptic vesicles with slower exocytotic kinetics. Heterogeneity in kinetic elements, therefore, favored synaptic responses with an early peak and a sustained phase. The application of cyclothiazide (CTZ) revealed that desensitization of postsynaptic receptors contributed to synaptic depression, which was more pronounced during stronger stimulation. Thus, desensitization had a twofold effect: It abbreviated signaling between IHC and the auditory nerve and also balanced differences in decay kinetics between responses to different stimulation strengths. We therefore propose that both pre- and postsynaptic mechanisms at the IHC ribbon synapse contribute to synaptic depression at the IHC ribbon synapse and spike rate adaptation in the auditory nerve.
Palabras clave:
Hair Cell
,
Ribbon Synapse
,
Synaptic Depression
,
Auditory Nerve
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Identificadores
Colecciones
Articulos(INGEBI)
Articulos de INST.DE INVEST.EN ING.GENETICA Y BIOL.MOLECULAR "DR. HECTOR N TORRES"
Articulos de INST.DE INVEST.EN ING.GENETICA Y BIOL.MOLECULAR "DR. HECTOR N TORRES"
Citación
Goutman, Juan Diego; Mechanisms of synaptic depression at the hair cell ribbon synapse that support auditory nerve function; National Academy of Sciences; Proceedings of the National Academy of Sciences of The United States of America; 114; 36; 9-2017; 9719-9724
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