What does this research mean for the field?

Milrinone exerts its positive inotropic effect primarily through potent inhibition of cyclic AMP phosphodiesterase, leading to increased cyclic AMP accumulation, without directly affecting sarcoplasmic reticulum calcium uptake or binding to beta-adrenergic or cholinergic muscarinic receptors. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

To determine the biochemical and receptor-level mechanisms responsible for the positive inotropic effects of the cardiotonic drug milrinone.

January 1, 1987Journal of Cardiovascular Pharmacology

Biochemical Mechanisms for the Inotropic Effect of the Cardiotonic Drug Milrinone

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Authors

CECraig Q. EarlTeva Pharmaceuticals (United States)JLJoel LindenCross-Cutting Cardiology WWWilliam B. WeglickiGeorge Washington University

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Implication

Explores milrinone mechanisms in vitro; leaves open clinical relevance for refractory heart failure.

Key Points

To determine the biochemical and receptor-level mechanisms responsible for the positive inotropic effects of the cardiotonic drug milrinone.
Assayed sarcoplasmic reticulum 45Ca-uptake and Ca-ATPase activity in cardiac myocytes treated with milrinone and amrinone.
Conducted radioligand receptor binding assays for adenosine, beta-adrenergic, and cholinergic muscarinic receptors.
Measured cyclic AMP accumulation and determined inhibition kinetics across high-affinity and low-affinity forms of cardiac cyclic AMP phosphodiesterase.
Milrinone demonstrated 40-fold greater phosphodiesterase inhibition than amrinone, selectively inhibiting the high-affinity form (Ki = 22 microM) compared to the low-affinity form (Ki = 225 microM).
Milrinone concentrations that increased cyclic AMP accumulation mirrored positive inotropic responses, following a potency rank of IBMX > milrinone > theophylline > caffeine > amrinone.
Milrinone had no effect on myocyte sarcoplasmic reticulum Ca-uptake or Ca-ATPase, but exhibited weak adenosine receptor binding (KD = 466 microM) and blocked adenosine agonist-induced negative inotropy.

Cite This Study

Earl et al. (1987) studied this question.

synapsesocial.com/papers/6a1b6c0b0ea968f653abd442 https://doi.org/10.1097/00005344-198709010-00031

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Biochemical Mechanisms for the Inotropic Effect of the Cardiotonic Drug Milrinone

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Key Points

Cite This Study

Biochemical Mechanisms for the Inotropic Effect of the Cardiotonic Drug Milrinone

Discussion

Member takes

Implication

Key Points

Cite This Study

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