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.