Properties of cholinergic receptor-mediated ion channels on type I vestibular hair cells of guinea pigs / 生理学报
Acta Physiologica Sinica
;
(6): 375-381, 2008.
Artículo
en Chino
| WPRIM
| ID: wpr-316716
ABSTRACT
To confirm the existence of cholinergic receptors on type I vestibular hair cells (VHCs I) of guinea pigs and to study the properties of the cholinergic receptor-mediated ion channels on VHCs I, electrophysiological responses of isolated VHCs I to external ACh were examined by means of whole-cell patch-clamp recordings. The results showed that 7.5% (21/279) VHCs I were found to be sensitive to ACh (10-1000 μmol/L). ACh generated an outward current in a steady, slow, dose-dependent [EC(50) was (63.78±2.31) μmol/L] and voltage-independent manner. In standard extracellular solution, ACh at the concentration of 100 μmol/L triggered a calcium-dependent current of (170±15) pA at holding potential of -50 mV, and the current amplitude could be depressed by extracellularly added calcium-dependent potassium channel antagonist TEA. The time interval for the next complete activation of ACh-sensitive current was no less than 1 min. The ion channels did not shut off even when they were exposed to ACh for an extended period of time (8 min). The results suggest that dose-dependent, calcium-dependent and voltage-independent cholinergic receptors were located on a few of the VHCs I investibular epithelium of guinea pigs. The cholinergic receptors did not show desensitization to ACh. This work reveals the existence of efferent neurotransmitter receptors on VHCs I and helps in understanding the function of vestibular efferent nervous system, and may provide some useful information on guiding the clinical rehabilitative treatment of vertigo.
Texto completo:
Disponible
Índice:
WPRIM (Pacífico Occidental)
Asunto principal:
Farmacología
/
Fisiología
/
Acetilcolina
/
Receptores Colinérgicos
/
Células Ciliadas Vestibulares
/
Técnicas de Placa-Clamp
/
Canales de Potasio Calcio-Activados
/
Bloqueadores de los Canales de Potasio
/
Cobayas
/
Potenciales de la Membrana
Límite:
Animales
Idioma:
Chino
Revista:
Acta Physiologica Sinica
Año:
2008
Tipo del documento:
Artículo
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