SPERM-INDUCED CALCIUM OSCILLATIONS OF HUMAN OOCYTES SHOW DISTINCT FEATURES IN OOCYTE CENTER AND PERIPHERY

• Type: Article in International Scientific Journal
• Date: 1995

Authors

TESARIK, J (Author) Other; sousa, m (Author) ICBAS; MENDOZA, C (Author) Other

Journal

Title: Molecular Reproduction and Development

Vol. 41

Pages: 257-263

ISSN: 1040-452X

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 40 Citations

Scopus - 42 Citations

Other information

Authenticus ID: P-001-GV5

Abstract (EN): Temporal and spatial characteristics of explosive periodic increases (spikes) of intracellular free Ca2+ concentration ([Ca2+]i) induced by sperm in human oocytes (Ca2+ oscillations) were analyzed by confocal laser scanning microscopy and compared to Ca2+ oscillations induced in oocytes by the thiol reagent thimerosal. During the steady-state period of sperm-induced Ca2+ oscillations, each individual [Ca2+]i spike invariably began from a focus in oocyte periphery and spread throughout the entire peripheral region before propagating to the central ooplasm. This peripheral Ca2+ wave was immediately followed by an explosive [Ca2+]i increase in the central ooplasm. However, this central [Ca2+]i rise only peaked when [Ca2+]i in the peripheral ooplasm was already on the decline. Moreover, the peak [Ca2+]i values were always considerably higher in the oocyte center than in the periphery. In contrast, thimerosal-induced Ca2+ oscillations did not show this particular form of propagation. These data show that sperm-induced Ca2+ oscillations have a unique pattern of spatial dynamics and suggest that the bulk of Ca2+ mobilized during each spike is released from stores that have a relatively high threshold for Ca2+-induced Ca2+ release (CICR). These stores are poorly developed, if not absent, in the oocyte cortex, and CICR from them is triggered by previous CICR from another type of store with a lower threshold that are preferentially located in the oocyte cortex and act as a detonator. (C) 1995 Wiley-Liss, Inc.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7