Intrapericardial blocking agents have extracardiac effects in dogs.
Am J Physiol
; 266(6 Pt 2): R1970-5, 1994 Jun.
Article
en En
| MEDLINE
| ID: mdl-7912904
The purpose of this study was to determine if intrapericardial infusion of hexamethonium, propranolol, or atropine affected extracardiac receptors in anesthetized dogs. Intrapericardial hexamethonium (> or = 25 mg) decreased renal sympathetic nerve activity (RSNA) in a dose-dependent fashion. After 250 mg, RSNA began to decrease in 65 +/- 7 s. Whereas vagal stimulation caused a muscarinic receptor-mediated increase in tracheal smooth muscle tone (as indicated by a 9.6 +/- 1.1 mmHg increase in endotracheal cuff pressure), the increase in cuff pressure (1.8 +/- 0.4 mmHg) was attenuated after intrapericardial tropine (4 mg). When the ansa and vagus were stimulated simultaneously, beta-adrenergic receptor-mediated smooth muscle relaxation opposed the muscarinic receptor-mediated constriction resulting in an increase in cuff pressure of only 3.6 +/- 0.9 mmHg. After intrapericardial propranolol (8 mg), simultaneous ansa and vagal stimulation caused a 7.0 +/- 1.6 mmHg increase in cuff pressure, demonstrating that intrapericardial propranolol blocked beta-adrenergic receptor-mediated relaxation of tracheal smooth muscle. These results show that hexamethonium, atropine, and propranolol infused intrapericardially have extracardiac effects.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Pericardio
/
Propranolol
/
Atropina
/
Tráquea
/
Compuestos de Hexametonio
/
Músculo Liso
Límite:
Animals
Idioma:
En
Revista:
Am J Physiol
Año:
1994
Tipo del documento:
Article