Developmental changes in calcium content of ultrastructurally distinct subcellular compartments of preimplantation human embryos

• Type: Article in International Scientific Journal
• Date: 1997

Authors

sousa, m (Author) ICBAS; barros, a (Author) FMUP; Silva, J (Author) Other; Tesarik, J (Author) Other

Journal

Title: Molecular Human Reproduction

Vol. 3

Pages: 83-90

ISSN: 1360-9947

Publisher: Oxford University Press

Indexing

ISI Web of Knowledge - 53 Citations

Scopus - 63 Citations

Other information

Authenticus ID: P-001-C28

DOI: 10.1093/molehr/3.2.83

Abstract (EN): The ultrastructural localization of mobilizable Ca2+ in different subcellular compartments of human oocytes and preimplantation embryos was studied using the potassium-pyroantimonate technique and transmission electron microscopy; the specificity was confirmed by chelation experiments and X-ray microanalysis, In unfertilized oocytes, Ca2+ was detected in small vesicles beneath the plasma membrane as well as in other forms of smooth endoplasmic reticulum (SER) and in mitochondria but not in cortical granules. In pronuclear zygotes and blastomeres of cleaving embryos, Ca2+-rich vesicles were no longer present close to the plasma membrane, and the entire cell periphery was poor in Ca2+-containing organelles which, however, were abundant in the perinuclear region. The uneven Ca2+ loading of SER and mitochondria from the pronuclear stage onwards suggests that Ca2+ release from both these types of organelle contributes to the embryonic Ca2+ signals. During mitosis, less Ca2+ was detected within organelles, but the antimonate reaction product was more abundant in the cytosol. These data suggest that, in addition to different forms of SER, mitochondria also act as a source of mobilizable Ca2+ in preimplantation human embryos. The previously described developmental and cell cycle related changes in the characteristics of Ca2+ signals are associated with the redistribution and structural reorganization of these organelles.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8