title: An insufficient increase of cytosolic free calcium level results postovulatory aging-induced abortive spontaneous egg activation in rat.
abstract: OBJECTIVE
  The present study was aimed to find out whether postovulatory aging-induced abortive spontaneous egg activation (SEA) is due to insufficient increase of cytosolic free Ca(2+) level.
  
  
  METHODS
  Immature female rats (22-24 days old) were subjected to superovulation induction protocol. Eggs were collected 14, 17 and 19 h post-hCG surge to induce in vivo egg aging. The eggs were collected 14 h post-hCG surge and cultured in vitro for 3, 5 and 7 h to induce in vitro egg aging. The morphological changes, rate of abortive SEA, chromosomal status and cytosolic free Ca(2+) levels were analyzed.
  
  
  RESULTS
  Postovulatory aging induced morphological features characteristics of abortive SEA in a time-dependent manner in vivo as well as in vitro. The extracellular Ca(2+) increased rate of abortive SEA during initial period of culture, while co-addition of a nifedipine (L-type Ca(2+) channel blocker) protected against postovulatory aging-induced abortive SEA. However, CI induced morphological features characteristics of egg activation (EA) in a dose-dependent manner. As compare to control, an increase of cytosolic free Ca(2+) level (1.42 times) induced abortive SEA, while further increase of cytosolic free Ca(2+) level (2.55 times) induced EA.
  
  
  CONCLUSIONS
  Our results show that an insufficient cytosolic free Ca(2+) level is associated with postovulatory aging -induced abortive SEA, while furthermore increase is required to induce EA in rat.
authors.affiliation: Cell Physiology Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221005, India.
authors.forename: Karuppanan V
authors.initials: KV
authors.lastname: Premkumar
authors.forename: Shail K
authors.initials: SK
authors.lastname: Chaube
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D016922:Cellular Senescence; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D033481:Chromosomes, Mammalian / Q000378:metabolism; D003470:Culture Media / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D059566:M Phase Cell Cycle Checkpoints; D010060:Ovulation / Q000187:drug effects / Q000378:metabolism*; D010063:Ovum / Q000187:drug effects / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats; D013997:Time Factors; D014966:Xanthenes / Q000378:metabolism
chemical_list: D000814:Aniline Compounds; D006063:Chorionic Gonadotropin; D003470:Culture Media; D014966:Xanthenes; C059715:Fluo-3; D000001:Calcimycin; D002118:Calcium