Key result
Alpha-adrenoceptor stimulation produced minimal changes in force of contraction in guinea-pig ventricles, but large increases in rabbit ventricles unrelated to slow inward calcium current changes.
Why the study?
Does alpha-adrenoceptor stimulation alter excitation and contraction in guinea-pig and rabbit ventricular heart muscle compared to beta-adrenoceptor stimulation?
Population
Ventricular preparations (papillary muscles and isolated myocytes) from guinea-pigs and rabbits
Comparison
Alpha-adrenoceptor stimulation vs Beta-adrenoceptor stimulation
Design
Preclinical
Authors
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Species differences in alpha-adrenergic ventricular inotropy caution against extrapolation; leaves open human relevance.
Does alpha-adrenoceptor stimulation alter excitation and contraction in guinea-pig and rabbit ventricular heart muscle compared to beta-adrenoceptor stimulation?
Alpha-adrenoceptor stimulation increases force of contraction in rabbit ventricles without changing slow inward calcium current, whereas its contribution in guinea-pig ventricles is minimal.
Hescheler et al. (1988) studied Ventricular heart muscle physiology. Alpha-adrenoceptor stimulation vs. Beta-adrenoceptor stimulation was evaluated on Mechanical and electrophysiological parameters (action potential, force of contraction, ionic currents). Alpha-adrenoceptor stimulation produced minimal changes in force of contraction in guinea-pig ventricles, but large increases in rabbit ventricles unrelated to slow inward calcium current changes.
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