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. 1969 Jun 1;53(6):758–780. doi: 10.1085/jgp.53.6.758

Electrophysiological Actions of Oxytocin on the Rabbit Myometrium

A L Kleinhaus 1, C Y Kao 1
PMCID: PMC2202874  PMID: 5783010

Abstract

The electrical activities of myometrial cells of the pregnant rabbit uterus have been studied by means of sucrose-gap and intracellular micro-electrode recording techniques. The resting potential of the myometrial cell was about -50 mv, and it is unaffected by the duration of pregnancy or placental attachment. Action potentials of the myometrium, although dependent on external Na+, were not always of the regenerative type; preparations from nonparturient uteri often produce mainly small spikes. The mean spike amplitude was 35 mv, rising at a mean maximum rate of 3 v/sec. Oxytocin, in concentrations less than 500 µU/ml, increased the mean spike amplitude to 48 mv and the mean maximum rate of rise to 7 v/sec, without affecting the resting potential. The relation between membrane potential and dV/dt of the spike was steepened by oxytocin, suggesting that oxytocin increased the number of normally sparse sodium gates in the myometrial membrane. By this action, oxytocin is believed to increase the probability of successful regenerative spikes and thereby initiate electrical activity in quiescent preparations, increase the frequency of burst discharges, the number of spikes in each burst, and the amplitude of spikes in individual cells.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. CSAPO A. I., CORNER G. W. The antagonistic effects of estrogen and progesterone on the staircase phenomenon in uterine muscle. Endocrinology. 1952 Nov;51(5):378–385. doi: 10.1210/endo-51-5-378. [DOI] [PubMed] [Google Scholar]
  2. CSAPO I. A., KURIYAMA H. A. Effects of ions and drugs on cell membrane activity and tension in the postpartum rat myometrium. J Physiol. 1963 Mar;165:575–592. doi: 10.1113/jphysiol.1963.sp007081. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. DANIEL E. E., SINGH H. The electrical properties of the smooth muscle cell membrane. Can J Biochem Physiol. 1958 Sep;36(9):959–975. [PubMed] [Google Scholar]
  4. Dale H. H. The Action of Extracts of the Pituitary Body. Biochem J. 1909;4(9):427–447. doi: 10.1042/bj0040427. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. GOTO M., CSAPO A. The effect of the ovarian steroids on the membrane potential of uterine muscle. J Gen Physiol. 1959 Nov;43:455–466. doi: 10.1085/jgp.43.2.455. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. GOTO M. The effects of oxytocin on the transmembrane potentials of the rat myometrium. Jpn J Physiol. 1960 Aug 15;10:427–435. doi: 10.2170/jjphysiol.10.427. [DOI] [PubMed] [Google Scholar]
  7. KAO C. Y. Contents and distributions of potassium, sodium, and chloride in uterine smooth muscle. Am J Physiol. 1961 Oct;201:717–722. doi: 10.1152/ajplegacy.1961.201.4.717. [DOI] [PubMed] [Google Scholar]
  8. KAO C. Y., GLUCK S. Contractile activities of mammalian smooth muscles in chloride-deficient media. Am J Physiol. 1961 Apr;200:658–666. doi: 10.1152/ajplegacy.1961.200.4.658. [DOI] [PubMed] [Google Scholar]
  9. KAO C. Y. Long-term observations of spontaneous electrical activity of the uterine smooth muscle. Am J Physiol. 1959 Feb;196(2):343–350. doi: 10.1152/ajplegacy.1959.196.2.343. [DOI] [PubMed] [Google Scholar]
  10. KAO C. Y., NISHIYAMA A. OVARIAN HORMONES AND RESTING POTENTIAL OF RABBIT UTERINE SMOOTH MUSCLE. Am J Physiol. 1964 Oct;207:793–799. doi: 10.1152/ajplegacy.1964.207.4.793. [DOI] [PubMed] [Google Scholar]
  11. KAO C. Y., ZAKIM D., BRONNER F. Sodium influx and excitation in uterine smooth muscle. Nature. 1961 Dec 23;192:1189–1190. doi: 10.1038/1921189a0. [DOI] [PubMed] [Google Scholar]
  12. Kao C. Y., Stanfield P. R. Actions of some anions on electrical properties and mechanical threshold of frog twitch muscle. J Physiol. 1968 Sep;198(2):291–309. doi: 10.1113/jphysiol.1968.sp008607. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. MARSHALL J. M., CSAPO A. I. Hormonal and ionic influences on the membrane activity of uterine smooth muscle cells. Endocrinology. 1961 Jun;68:1026–1035. doi: 10.1210/endo-68-6-1026. [DOI] [PubMed] [Google Scholar]
  14. Marshall J. M. Relation between the ionic environment and the action of drugs on the myometrium. Fed Proc. 1968 Jan-Feb;27(1):115–119. [PubMed] [Google Scholar]
  15. Tomita T. Electrical responses of smooth muscle to external stimulation in hypertonic solution. J Physiol. 1966 Mar;183(2):450–468. doi: 10.1113/jphysiol.1966.sp007876. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. WOODBURY J. W., McINTYRE D. M. Electrical activity of single muscle cells of pregnant uteri studied with intracellular ultra-microelectrodes. Am J Physiol. 1954 Jun;177(3):355–360. doi: 10.1152/ajplegacy.1954.177.3.355. [DOI] [PubMed] [Google Scholar]

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