PMID: 2480484Jan 1, 1989Paper

Effects of the phosphodiesterase inhibitor enoximone on the autonomic innervation of the isolated heart.

Journal of Cardiovascular Pharmacology
K LöffelholzR Lindmar

Abstract

Enoximone is a selective inhibitor of a low Km, cyclic AMP-specific type of phosphodiesterase (PDE III). In guinea pig and chicken atria, enoximone (0.1-100 mumol/L) caused a weak increase in the force of contraction. The heart rate was slightly enhanced or was unchanged (chicken). Enoximone (30 mumol/L) also failed to shift the concentration-response curves for the positive inotropic and chronotropic effects of norepinephrine in guinea pig atria. Under almost the same conditions, enoximone and the nonselective PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX) markedly potentiated the forskolin-induced mobilization of choline from phospholipids. The concentrations of IBMX (100 mumol/L) and of enoximone (50 mumol/L) used were equieffective and did not enhance choline mobilization by themselves. Cardioinhibition caused by acetylcholine was unaffected by enoximone. In perfused guinea pig hearts, the release of [3H]norepinephrine evoked by field stimulation (5 Hz) was increased by 50 mumol/L enoximone both in the absence and presence of cocaine plus corticosterone. In contrast, enoximone failed to alter the release of acetylcholine in chicken hearts at rest and during field stimulation (5 Hz), which directly depolarizes the intrinsi...Continue Reading

Citations

Dec 15, 1989·Analytical Chemistry·S Andersson-EngelsK Svanberg

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