Chloride and monovalent ion-selective cation currents activated by oxytocin in pregnant rat myometrial cells

Arnaudeau, Serge; Leprêtre, Nathalie; Mironneau, Jean

doi:10.1016/0002-9378(94)90288-7

Cited by 36 publications

(23 citation statements)

References 25 publications

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“…In addition to its role as a powerful contractile agent, OT indirectly augments myometrial contractility by stimulating prostaglandin biosynthesis in the decidua (22,23). Furthermore, OT in human myometrium is intricately linked to Ca 2ϩ signaling in which its application induces activation of both nonselective cation and chloride conductances in pregnant rat myometrium (24) and mobilization of intracellular Ca 2ϩ after phosphoinositide hydrolysis via phospholipase C and G proteins of the G␣(q/11) subclass (25). Our novel observation that decidual I Ca(T) observed after the onset of labor is much more sensitive to OT than that of nonlabor decidual cells is intriguing and suggests a possible role for this channel in the temporal control of labor.…”

Section: Discussionmentioning

confidence: 99%

Oxytocin Inhibits T-Type Calcium Current of Human Decidual Stromal Cells

Liu

Hill

Khan

2005

The Journal of Clinical Endocrinology &Amp; Metabolism

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Section: Discussionmentioning

confidence: 99%

Oxytocin Inhibits T-Type Calcium Current of Human Decidual Stromal Cells

Liu

Hill

Khan

2005

The Journal of Clinical Endocrinology &Amp; Metabolism

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“…Using myometrial tissue from women undergoing cesarean section throughout the third trimester, Bird et al [4] found that nifedipine produced a concentration-related decrease in oxytocin-stimulated contraction strength without a consistent increase in interval contractions. Arnaudeau et al [16] demonstrated that stimulation of oxytocin receptors induced opening of calcium-activated chloride and cation channels, leading to depolarization of the myometrial cells and that this depolari- zation opens, in turn, voltage-dependent calcium channels. Izumi et al [17] suggested that agonists such as carbachol, prostaglandin F 2· , and prostaglandin E 2 enhanced the calcium effects on the contractile elements through G protein-mediated mechanisms in late gestation rat myometrium.…”

Section: Discussionmentioning

confidence: 99%

Inhibitory Effects of Isradipine on Spontaneous and Oxytocin- and Carbachol-Stimulated Contractions of Rat Myometrium

Çetin¹,

Kaya²,

Çetin

et al. 1998

Pharmacology

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Our aim was to investigate the effect of isradipine, a second-generation calcium channel blocker, on spontaneous and oxytocin- and carbachol-stimulated contractions of myometrium isolated from nonpregnant and pregnant rats. Amplitude, frequency, duration and integrated area of spontaneous and oxytocin- and carbachol-stimulated contractions of nonpregnant and pregnant rat myometrium were compared before and after the treatment with isradipine (10^–6 to 10^–4 mol/l). Isradipine inhibited contractions of myometrial strips isolated from nonpregnant and pregnant rats in a concentration-dependent manner, with a significant effect on the amplitude (10^–5 to 10^–4 mol/l) and integrated area (3 × 10^–6 to 10^–4 mol/l) of spontaneous and oxytocin- and carbachol-stimulated contractions. Isradipine induced similar concentration-dependent effects on the frequency and duration of spontaneous and carbachol-stimulated contractions at higher concentrations (3 × 10^–5 to 10^–4 mol/l) but had no effect on frequency and duration of oxytocin-stimulated contractions. Isradipine appears to be an effective relaxant in rat myometrium. This effect of isradipine may become therapeutically advantageous in clinical application for preterm labor.

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“…Very little, however, is known about Cl Ca in the myometrium. The channels have been reported [7] and suggested to be activated following oxytocin stimulation of the uterus [3,4]. It is not known, however, if Ca 2+ entry via L-type Ca 2+ channels can activate these channels, although there are reports that this occurs in other tissues [1,11,23] There has been no study of the role of Ca 2+ -activated Cl − channels in contraction of the myometrium, apart from that of [43].…”

Section: Introductionmentioning

confidence: 99%

Electrophysiological characterization and functional importance of calcium-activated chloride channel in rat uterine myocytes

Jones

Shmygol

Kupittayanant

et al. 2004

Pfl�gers Archiv European Journal of Physiology

109

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In order to better understand the mechanisms underlying excitation of the uterus, we have elucidated the characteristics and functional importance of Ca(2+)-activated Cl(-) currents ( I(Cl-Ca)) in pregnant rat myometrium. In 101/320 freshly isolated myocytes, there was a slowly inactivating tail current (162+/-48 pA) upon repolarization following depolarising steps. This current has a reversal potential close to that for chloride, and was shifted when [Cl(-)] was altered. It was activated by Ca(2+) (but not Ba(2+)) entry through L-type Ca(2+) channels, enhanced by the Ca(2+) channel agonist Bay K8644 (2 microM), and inhibited by the Cl(-) channel blockers, niflumic acid (10 microM) and anthracene-9-carboxylic acid (9-AC, 100 microM). We therefore conclude that the pregnant rat myometrium contains Ca(2+)-activated Cl(-) channels producing inward current in ~30% of its cells. When these channels were inhibited by niflumic acid or 9-AC in intact tissues, the frequency of spontaneous contractions, was significantly reduced. Niflumic acid was also shown to inhibit oxytocin-induced contractions and Ca(2+) transients. Neither 9-AC nor niflumic acid had any effect on high-K-invoked contractions. Taken together these data suggest that Ca(2+)-activated Cl(-) channels are activated by Ca(2+) entry and play a functionally important role in myometrium, probably by contributing to membrane potential and firing frequency (pacemakers) in these cells.

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Chloride and monovalent ion-selective cation currents activated by oxytocin in pregnant rat myometrial cells

Cited by 36 publications

References 25 publications

Oxytocin Inhibits T-Type Calcium Current of Human Decidual Stromal Cells

Oxytocin Inhibits T-Type Calcium Current of Human Decidual Stromal Cells

Inhibitory Effects of Isradipine on Spontaneous and Oxytocin- and Carbachol-Stimulated Contractions of Rat Myometrium

Electrophysiological characterization and functional importance of calcium-activated chloride channel in rat uterine myocytes

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