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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Adrenergic alpha-1 Receptor Agonists, Adrenergic alpha-1 Receptor Antagonists, Adrenergic beta-Antagonists, Animals, Atrial Function, Left, Heart Ventricles, In Vitro Techniques, Inositol Phosphates, Male, Myocardial Contraction, Norepinephrine, Phenylephrine, Rats, Rats, Wistar, Receptors, Adrenergic, alpha-1, Receptors, Adrenergic, beta, Stimulation, Chemical.
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Do beta-Adrenoceptors potentiate alpha1-adrenoceptor-mediated inotropic response in rat left atria? Context: To investigate whether stimulation of beta-adrenoceptor (AR) and its subtypes augment alpha1-AR-evoked positive inotropic response and inositol phosphate (InsP) accumulation in isolated rat left atria. Inotropic response was determined by contractile function experiment in isolated electrically driven rat left atria. 3H-InsP accumulations were measured by 3H-inositol incorporation and column chromatography. (1) Stimulation of alpha1-AR by phenylephrine (PE) or norepinephrine (NE) in the presence of propranolol (Prop) evoked positive inotropic response and 3H-InsP accumulations, while stimulation of beta-AR by isoprenaline (ISO) or NE in the presence of phentolamine (Phen) only evoked positive inotropic response, but not 3H-InsP accumulations. (2) Simultaneous stimulation of alpha1- and beta-AR by NE or ISO plus PE significantly shifted the concentration-dependent inotropic response curves and 3H-InsP accumulation curves to the left and upward compared with individual alpha1-AR stimulation by PE or NE in the presence of Prop. (3) In the presence of ICI118551 (selective beta2-AR antagonist) or CGP12177 (selective beta1-AR antagonist), stimulation of either beta1- or beta2-AR did not change alpha1-AR-evoked inotropic response and 3H-InsP accumulations.
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Stimulation of beta1-AR and beta2-AR potentiates alpha1-AR-mediated positive inotropic response and InsP accumulation in isolated rat left atria. Final Decision: yes