Differential effects of cocaine on the positive inotropic effect of noradrenaline mediated by α1- and β-adrenoceptors in failing human myocardium
| Autor: | O. Geiran, Tor Skomedal, Halfdan Aass, Jan-Bjørn Osnes |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Adult
Male Inotrope medicine.medical_specialty Sympathetic nervous system Synaptic cleft Population Adrenergic Stimulation Norepinephrine chemistry.chemical_compound Cocaine Internal medicine Receptors Adrenergic beta medicine Humans Vasoconstrictor Agents Drug Interactions education Neurotransmitter Pharmacology education.field_of_study business.industry Heart Middle Aged Receptors Adrenergic alpha Myocardial Contraction Endocrinology medicine.anatomical_structure chemistry Female business medicine.drug |
| Zdroj: | European Journal of Pharmacology. 419:223-230 |
| ISSN: | 0014-2999 |
| Popis: | Electrically driven (1 Hz) ventricular trabeculae from explanted failing human myocardium were indirectly examined for the localization of the alpha1-adrenoceptor population and the beta-adrenoceptor population in relation to sympathetic nerve endings. We examined the influence of neuronal uptake blockade by cocaine upon the horizontal position of the concentration-response curves for the inotropic effects exerted by noradrenaline in the presence and absence of appropriate adrenoceptor antagonists. Cocaine shifted the concentration-response curve for alpha1-adrenoceptor stimulation, but not that for beta-adrenoceptor stimulation, to lower concentrations of noradrenaline in a parallel manner. The concentration-response curve for combined adrenoceptor stimulation was shifted by cocaine to lower concentrations of noradrenaline in a nonparallel manner. In explanted allograft heart, cocaine had no effect upon the position of the concentration-response curve to alpha1-adrenoceptor stimulation. The data indicate that in the explanted native hearts the alpha1-adrenoceptor population is located close to or within the synaptic cleft, while the beta-adrenoceptor population remaining in the failing myocardium is located more distantly to the neuronal release sites. |
| Databáze: | OpenAIRE |
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