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

• Tipo: Artigo em Revista Científica Internacional
• Data: 1997

Autores

sousa, m (Autor) ICBAS; barros, a (Autor) FMUP; Silva, J (Autor) Outra; Tesarik, J (Autor) Outra

Revista

Título: Molecular Human Reproduction

Vol. 3

Páginas: 83-90

ISSN: 1360-9947

Editora: Oxford University Press

Indexação

ISI Web of Knowledge - 53 Citações

Scopus - 63 Citações

Outras Informações

ID Authenticus: 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.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 8