Characterization of the tissue-level Ca2+ signals in spontaneously contracting human myometrium

Gilles Bru-Mercier, Joanna E. Gullam, Steven Thornton, Andrew M. Blanks, Anatoly Shmygol

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

In the labouring uterus, millions of myocytes forming the complex geometrical structure of myometrium contract in synchrony to increase intrauterine pressure, dilate the cervix and eventually expel the foetus through the birth canal. The mechanisms underlying the precise coordination of contractions in human myometrium are not completely understood. In the present study, we have characterized the spatio-temporal properties of tissue-level [Ca2+]i transients in thin slices of intact human myometrium. We found that the waveform of [Ca2+]i transients and isotonic contractions recorded from thin slices was similar to the waveform of isometric contractions recorded from the larger strips in traditional organ bath experiments, suggesting that the spatio-temporal information obtained from thin slices is representative of the whole tissue. By comparing the time course of [Ca2+]i transients in individual cells to that recorded from the bundles of myocytes we found that the majority of myocytes produce rapidly propagating long-lasting [Ca2+]i transients accompanied by contractions. We also found a small number of cells showing desynchronized [Ca2+]i oscillations that did not trigger contractions. The [Ca2+]i oscillations in these cells were insensitive to nifedipine, but readily inhibited by the T-type Ca2+ channel inhibitor NNC55-0396. In conclusion, our data suggest that the spread of [Ca2+]i signals in human myometrium is achieved via propagation of long-lasting action potentials. The propagation was fast when action potentials propagated along bundles of myocytes and slower when propagating between the bundles of uterine myocytes.

Original languageEnglish
Pages (from-to)2990-3000
Number of pages11
JournalJournal of Cellular and Molecular Medicine
Volume16
Issue number12
DOIs
Publication statusPublished - Dec 2012
Externally publishedYes

Keywords

  • Calcium channel inhibitors
  • Calcium signalling
  • Human myometrium
  • Spontaneous activity
  • Uterine contractility

ASJC Scopus subject areas

  • Molecular Medicine
  • Cell Biology

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