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Ouabain stimulates slowly adapting pulmonary stretch receptors / 生理学报
Acta Physiologica Sinica ; (6): 689-695, 2005.
Artículo en Inglés | WPRIM | ID: wpr-334116
ABSTRACT
Ouabain, a Na(+)/K(+)-ATPase inhibitor, induces slowly adapting pulmonary stretch receptors (SARs) to discharge paradoxically. Paradoxical discharge is characterized by increased SAR activity during lung deflation coupled with silence during lung inflation. We hypothesized that over-excitation silences the SARs. Accordingly, if cyclic inflation pressure was reduced so as to lower SAR stimulation, paradoxical discharge would be prevented. In the present study, single-unit activity of SARs was recorded in anesthetized, open-chest and mechanically ventilated rabbits with positive-end-expiratory pressure (PEEP). After microinjection of ouabain into the receptive field, SAR activity initially increased and then gradually became paradoxical. During paradoxical cycling, SAR activity started and stopped abruptly, oscillating between high frequency discharge during lung deflation and silence during peak inflation. Removing PEEP reduced basal cyclic stimulation and returned the discharge pattern to normal, that is, SAR activity was highest at peak inflation pressure but silent during deflation. It is speculated that stretching SARs causes Na(+) influx, producing generator potential (GP). Normally, GP recovers by Na(+) extrusion via Na(+)/K(+)-ATPase. Ouabain inhibits the ATPase, which limits Na(+) extrusion, and thus sustains the GP. Therefore, after ouabain microinjection, lung inflation will further increase GP, causing over-excitation to silence the SARs.
Asunto(s)
Texto completo: Disponible Índice: WPRIM (Pacífico Occidental) Asunto principal: Ouabaína / Farmacología / Fisiología / Receptores de Estiramiento Pulmonares / Nervio Vago / Potenciales de Acción / Adaptación Fisiológica / ATPasa Intercambiadora de Sodio-Potasio / Ventilación Pulmonar / Pulmón Límite: Animales Idioma: Inglés Revista: Acta Physiologica Sinica Año: 2005 Tipo del documento: Artículo

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Texto completo: Disponible Índice: WPRIM (Pacífico Occidental) Asunto principal: Ouabaína / Farmacología / Fisiología / Receptores de Estiramiento Pulmonares / Nervio Vago / Potenciales de Acción / Adaptación Fisiológica / ATPasa Intercambiadora de Sodio-Potasio / Ventilación Pulmonar / Pulmón Límite: Animales Idioma: Inglés Revista: Acta Physiologica Sinica Año: 2005 Tipo del documento: Artículo