Dexamethasone reverses the labor-associated myometrial desensitization to beta-adrenergic agonists in the rat

Article Abstract:

Dexamethasone appears to enhance the ability of beta-adrenergic agonists to inhibit muscle contraction at the time in delivery when beta-agonist induced desensitization is greatest. Beta-adrenergic agonists relax uterine muscle and are widely used to treat preterm labor. However, their effect is short-lived and of limited benefit. Uterine muscle samples were removed from pregnant and non-pregnant rats and from rats that had already delivered. The beta-adrenergic agonist isoproterenol initially reduced muscle contractions in samples from all groups. However contractions resumed after 10.45 hours in samples from virgin rats, after 7 to 9 hours in samples from the rats that had already delivered and after only 15 minutes in samples from the pregnant rats in labor. Dexamethasone had no significant effects on desensitization in muscle samples from either the virgin rats or the rats that had already delivered. However, in samples from rats in labor that were pre-treated with dexamethasone, isoproterenol inhibited contractions for 2.75 hours.

Myometrium, Dexamethasone, Adrenergic beta agonists, Adrenergic beta-agonists

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Is the attenuation of beta-adrenergic agonist efficacy during labor caused by elevated prostaglandin E levels?

Article Abstract:

Prostaglandin E in obstetrical labor may desensitize beta-adrenergic receptors in the myometrium, reducing the effectiveness of beta-agonists in the termination of premature uterine contractions. Researchers incubated mononuclear white blood cells from pregnant women at term and in labor, and from women not in labor. Cells from laboring women had significantly reduced beta-adrenergic receptor activity, and supplemental prostaglandin E substantially reduced beta-adrenergic receptor function on cells from nonlaboring women.

Prostaglandins E, Beta adrenoceptors, Adrenergic beta receptors

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Meloxicam effectively inhibits preterm labor uterine contractions in a chronically catheterized pregnant sheep model: Impact on the fetal blood flow and fetal-maternal physiologic parameters

Article Abstract:

The nonsteroidal anti-inflammatory drug meloxicam, a more selective cyclooxygenase-2 inhibitor, is found to effectively inhibit labor but avoid the complications associated with inhibition of cyclooxygenase-1. The evaluation of meloxicam has shown that it represents a potentially safe and effective tocolytic agent.

Health aspects, Complications and side effects, Drug therapy, Dosage and administration, Premature labor, Uterus, Uterine contractions, Meloxicam, Premature labour

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