Summary
The effects of prostaglandin F2α (PG) have been studied on the transmembrane potentials and contractions in isolated myometrial strips from pregnant rats. The results showed that: 1. The sensitivity of the myometrium to exogenous PG increases from day 19 to day 22 of gestation. 2. The electrical response to PG, at maximally effective doses (10−6 to 10−5 M) consists of a slow depolarization which upon reaching threshold initiates spike discharge. 3. These actions are most pronounced t term (day 22) and are due to a direct action of PG on the myometrical cells. 4. D-600 (a methoxy derivative of verapamil) abolishes spike discharge and the phasic contractions induced by PG but has no effect on the slow depolarization and the accompanying increase in tonic tension. 5. The slow depolarization is dependent upon the presence of sodium in the external environment and is unaffected by the removal of calcium. 6. The spikes (and phasic contractions) are dependent upon the presence of calcium in the external environment.
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Abe, Y.: Effects of changing the ionic environment on passive and active membrane properties of pregnant rat uterus. J. Physiol. (Lond.) 214, 173–190 (1971)
Anderson, N. C., Ramon, F., Snyder, A.: Studies on calcium and sodium in uterus smooth muscle excitation under current-clamp and voltage-clamp conditions. J. gen. Physiol. 58, 322–339 (1971)
Bianchi, C. P.: Pharmacology of excitation-contraction coupling in muscle. Introduction: Statement of the problem. Fed. Proc. 28, 1624–1627 (1969)
Carsten, M. E.: Role of calcium binding by sarcoplasmic reticulum in the contraction and relaxation of uterine smooth muscle. J. gen. Physiol. 53, 414–420 (1969)
Carsten, M. E.: Prostaglandins and oxytocin: Their effects on uterine smooth muscle. Prostaglandins 5, 33–40 (1974)
Challis, J. R. G.: Physiology and pharmacology of PGs in parturition. Prostaglandins 5, G-45–G-53 (1974)
Csapo, A. I.: The regulatory interplay of progesterone and prostaglandin F2α in the control of the pregnant uterus. In: Uterine contractions-side effects of steroidal contraceptives. Vol. 1 of Human reproduction. New York: Wiley Interscience 1973
de Paiva, C. E. N., Csapo, A. I.: The effect of prostaglandin on the electric activity of the pregnant uterus. Prostaglandins 4, 177–188 (1973)
Diamond, J., Marshall, J. M.: A comparison of the effects of various smooth muscle relaxants on the electrical and mechanical activity of the rat uterus. J. Pharmacol. exp. Ther. 168, 21–30 (1969)
Fleckenstein, A., Grün, G., Tritthardt, H., Byon, K.: Uterus-Relaxation durch hochaktive Ca2+-antagonistische Hemmstoffe der elektromechanischen Koppelung wie Isoption (Verapamil, Iproveratril), Substanz D-600 und Segontin (Prenylamin). Klin. Wschr. 49, 32–41 (1971)
Goldberg, V. J.: IonRamwell, P. W.: Role of prostaglandins in reproduction. Physiol. Rev. 55, 325–351 (1975)
Goodford, P. J.: Ionic interactions in smooth muscle. In: Smooth muscle. Baltimore: Williams and Wilkins 1970
Harney, P. J., Sneddon, J. M., Williams, K. I.: The influence of ovarian hormones upon the motility and prostaglandin production of the pregnant rat uterus in vitro. J. Endocr. 60, 343–351 (1974)
Hurwitz, L., Suria, A.: The link between agonist action and response in smooth muscle. Ann. Rev. Pharmacol. 11, 303–323 (1971)
Kohlhardt, M., Bauer, B., Krause, H., Fleckenstein, A.: Differnetiation of the transmembrane Na and Ca channels in mammalian cardiac fibres by the use of specific inhibitors. Pflügers Arch. 335, 309–322 (1972)
Kroeger, E. A., Marshall, J. M.: Beta-adrenergic effects on rat myometrium: Role of cyclic AMP. Amer. J. Physiol. 266, 1298–1303 (1974)
Marshall, J. M.: Relation between the ionic environment and the action of drugs on the myometrium. Fed. Proc. 27, 115–119 (1968)
Mironneau, J.: Excitation-contraction coupling in voltage-clamped uterine smooth muscle. J. Physiol. (Lond.) 223, 127–141 (1973)
Osa, T., Suzuki, H., Katase, T., Kurivama, H.: Excitatory action of synthetic prostaglandin E2 on the electrical activity of pregnant mouse myometrium in relation to temperature changes and external sodium and calcium concentrations. Jap. J. Physiol. 24, 233–248 (1974)
Reiner, O., Marshall, J. M.: Action of D-600 on spontaneous and electrically stimulated activity of parturient rat uterus. Naunyn-Schmiedeberg's Arch. Pharmacol. 290, 21–28 (1975).
Vane, J. W., Williams, K. I.: The contribution of prostaglandin production to contractions of the isolated rat uterus. Brit. J. Pharmacol. 48, 629–639 (1973)
Williams, K. I., Sneddon, J. M., Harvey, P. J.: Prostaglandin production by the pregnant rat uterus in vitro and its relevance to parturition. Pol. J. Pharmacol. Pharm. 26, 207–215 (1974)
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This study was supported by USPHS Grant HD-06963-9
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Reiner, O., Marshall, J.M. Action of prostaglandin, PGF2α, on the uterus of the pregnant rat. Naunyn-Schmiedeberg's Arch. Pharmacol. 292, 243–250 (1976). https://doi.org/10.1007/BF00517384
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DOI: https://doi.org/10.1007/BF00517384