Inotropic and sympathetic responses to the intracoronary infusion of a beta2-receptor agonist: a human in vivo study.
Circulation
; 99(18): 2402-7, 1999 May 11.
Article
em En
| MEDLINE
| ID: mdl-10318661
ABSTRACT
BACKGROUND:
On the basis of the presence of beta2-receptors within the sympathetic nervous system, beta2-stimulation may increase cardiac sympathetic outflow. We addressed the hypothesis that sympathoexcitatory beta2-receptors are present in the human left ventricle. METHODS ANDRESULTS:
The beta2-agonist salbutamol was infused into the left coronary artery in 3 groups of patients group 1 (n=9, no beta-blocker therapy), group 2 (n=7, beta1-selective blockade with atenolol), and group 3 (n=6, nonselective beta-blockade with nadolol). Left ventricular +dP/dt in response to increasing concentrations of salbutamol was measured in all groups, and cardiac norepinephrine spillover was measured in group 1. There were no systemic hemodynamic changes in any group. Salbutamol resulted in a 44+/-6% increase in +dP/dt in group 1, a 25+/-6% increase in group 2 (P<0.05 versus group 1), and no increase in group 3. Salbutamol also resulted in a 124+/-37% increase in cardiac norepinephrine spillover in group 1 (P<0.05).CONCLUSIONS:
Evidence that salbutamol increased norepinephrine release from cardiac sympathetic nerves was provided by the observations that atenolol suppressed the salbutamol inotropic response, demonstrating that this response was mediated in part by beta1-receptors and that salbutamol also resulted in an increase in cardiac norepinephrine spillover. This result provides in vivo evidence, in humans, for the role of sympathoexcitatory cardiac beta2-receptors.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sistema Nervoso Simpático
/
Simpatomiméticos
/
Agonistas Adrenérgicos beta
/
Doença das Coronárias
/
Albuterol
/
Agonistas de Receptores Adrenérgicos beta 2
/
Contração Miocárdica
Tipo de estudo:
Diagnostic_studies
Limite:
Adult
/
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
Circulation
Ano de publicação:
1999
Tipo de documento:
Article
País de afiliação:
Canadá