Developmental changes in modulation of contractility of rabbit hearts

Journal of Cardiovascular Pharmacology
T AkitaRonald W Joyner

Abstract

We recently described postnatal developmental differences of beta-adrenergic- and G-protein-mediated modulation of L-type calcium currents (ICa) in newborn and adult rabbit heart. To extend the results obtained by ICa experiments, we studied developmental changes in modulation of contractility induced by isoproterenol (ISO), forskolin (FOR) and isobutyl-methylxanthine (IBMX), all of which work through the cyclic AMP-dependent pathway. Left ventricular developed pressure (LVDP) and its first derivative (dP/dt) were measured with an intraventricular fluid-filled balloon in isolated adult and newborn (ages 1-3 days) rabbit hearts under Langendorff perfusion. ISO increased LVDP and +/- dP/dtmax dose dependently, with much greater positive inotropic effect on adult than on newborn heart. Concomitant use of a subthreshold concentration of IBMX (0.1 microM), a nonselective phosphodiesterase inhibitor (PDEI), did not significantly potentiate the dose-dependent inotropic effect of ISO in adult heart, but did markedly potentiate such effect in newborn heart. ISO 10 microM and FOR 10 microM had comparable inotropic effects on adult heart, whereas 10 microM ISO had a much weaker inotropic effect than 10 microM FOR on newborn heart. However...Continue Reading

Citations

Apr 11, 2018·Canadian Journal of Physiology and Pharmacology·B OstadalF Kolar
Oct 8, 2009·Circulation. Heart Failure·Daphne T Hsu, Gail D Pearson
Aug 1, 2014·Pediatric Critical Care Medicine : a Journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies·Janus A HyldebrandtHanne B Ravn

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