Effects of high potassium depolarization, carbachol and oxytocin on the lanthanum-resistant 45Ca fraction in rat myometrium.

Uruno, Tsutomu; Sekiguchi, Teruyuki; Sunagane, Nobuyoshi; Matsuoka, Yutaka; Kubota, Keiichi

doi:10.1254/jjp.33.1

Cited by 2 publications

(1 citation statement)

References 13 publications

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“…On the other hand, it has been reported that the high K+ induced contraction in rat uterus is under the influence of estrogen and progesteron (Ishii et al 1986, Takayama et al 1986, Uruno et al 1983. We have already reported that the decrease of the developed tension in isosmotically substituted high K+/Na+deficient solution in rat uterus of estrus phase is probably due to the cell swelling (Kamizaki et al 1988).…”

Section: Introductionmentioning

confidence: 97%

A change in inhibitory mechanism of Na+ deficiency on high K+-induced contraction in rat uterus with the progress of pregnancy.

Kamizaki

Shimizu

Nakajyo

et al. 1990

Jpn. J. Smooth Muscle Res.

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Section: Introductionmentioning

confidence: 97%

A change in inhibitory mechanism of Na+ deficiency on high K+-induced contraction in rat uterus with the progress of pregnancy.

Kamizaki

Shimizu

Nakajyo

et al. 1990

Jpn. J. Smooth Muscle Res.

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Changes in Intracellular Free Calcium in Isolated Myometrial Cells: Role of Extracellular and Intracellular Calcium and Possible Involvement of Guanine Nucleotide-Sensitive Proteins*

Anwer

Sanborn

1989

Endocrinology

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Intracellular free calcium concentrations were measured directly in rat myometrial cells loaded with fura-2. The basal concentrations of calcium were 148 +/- 5.0 and 137 +/- 3.7 nM in the presence and absence of 1 mM extracellular calcium, respectively. Oxytocin, carbachol, and norepinephrine rapidly and transiently increased intracellular free calcium, with half-maximal effects at 0.19, 9.9, and 5.3 microM, respectively. The maximal effects of these agents were reduced by 57%, 32%, and 36%, respectively, when the extracellular calcium was replaced by 2 mM EGTA. Pretreatment with pertussis toxin partially (47-57%) inhibited the contractant-induced increase in intracellular free calcium in the presence of 1 mM extracellular CaCl2 and produced an even greater inhibition (76-98%) in the absence of extracellular calcium. Pretreatment with D600 (30 microM) or amiloride (50 microM) and reduction of extracellular sodium did not affect the oxytocin-induced calcium increase. However, adenosine and the A2-receptor agonist N-ethylcarboxamidoadenosine did attenuate the effect of oxytocin in a dose-dependent manner. These data represent the first direct evidence that oxytocin, carbachol, and norepinephrine increase the intracellular free calcium concentration in the rat myometrium. The data suggest that contractants mobilize calcium from both extracellular and intracellular sources, the latter involving a pertussis toxin-sensitive mechanism.

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Effects of high potassium depolarization, carbachol and oxytocin on the lanthanum-resistant 45Ca fraction in rat myometrium.

Abstract: Abstract-The

Cited by 2 publications

References 13 publications

A change in inhibitory mechanism of Na+ deficiency on high K+-induced contraction in rat uterus with the progress of pregnancy.

A change in inhibitory mechanism of Na+ deficiency on high K+-induced contraction in rat uterus with the progress of pregnancy.

Changes in Intracellular Free Calcium in Isolated Myometrial Cells: Role of Extracellular and Intracellular Calcium and Possible Involvement of Guanine Nucleotide-Sensitive Proteins*

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