INGEBI   02650
INSTITUTO DE INVESTIGACIONES EN INGENIERIA GENETICA Y BIOLOGIA MOLECULAR "DR. HECTOR N TORRES"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Properties of the olivocochlear-outer hair cell synapse in the mouse cochlea
Autor/es:
JIMENA BALLESTERO; JAVIER ZORRILLA DE SAN MARTÍN; JUAN GOUTMAN; PAUL A. FUCHS; ANA BELÉN ELGOYHEN; ELEONORA KATZ
Lugar:
Huerta Grande, Córdoba, Argentina
Reunión:
Congreso; Segunda Reunión Conjunta de la Sociedad Argentina de Neurociencias (SAN) y el Taller Argentino de Neurociencias (TAN); 2010
Resumen:
In the Organ of Corti, the sensory epithelia of the mammalian auditory system, inner hair  cells  transduce  sound  stimuli  while  outer  hair  cells  (OHCs)  participate  in  the amplification of sound. OHC function is inhibited by efferent cholinergic olivocochlear (OC) fibers. OC fibers firing rate varies according to the type and intensity of sound. In turn, the degree of inhibition exerted by OC fibers on the auditory function changes with firing rates. In this work we study the properties of the OC synapse onto OHCs. Synaptic activity was recorded in voltage-clamped OHCs from the apical turn of the mouse cochlea (P10-12) during electrical stimulation of OC fibers. Activation of fibers by single shocks evoked inhibitory postsynaptic currents with a low rate of success. Paired-pulse protocols showed that this synapse facilitates with maximum efficacy at  10  ms  pulse  intervals.  Trains  of  stimulation  at  different  frequencies  produced increasing levels of transmitter release proportional to the stimulus frequency due both to summation and facilitation of synaptic responses. These results show that this synapse facilitates at physiological OC fibers firing frequencies. This property could be  relevant  for  encoding  different  degrees  of  OC  inhibition  in  response  to  variable sound stimulation.