Acetylcholine induces Ca 2+ oscillations via m3/m4 muscarinic receptors in the mouse oocyte

Dawon Kang, Jae-Yong Park, Jaehee Han, In Ha Bae, Sook Young Yoon, Sang Soo Kang, Wan Sung Choi, Seong Geun Hong

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13 Citations (Scopus)

Abstract

Changes in intracellular Ca 2+ concentration are required for the activation of mammalian oocytes. They are caused mainly by Ca 2+ release from the endoplasmic reticulum (ER) via InsP 3 receptors (InsP 3 R). Several studies have reported that acetylcholine (ACh) is capable of triggering early activation events in mouse oocytes over-expressed with the m1 muscarinic ACh receptor (m1AChR). Here we examined which subtypes of the mAChR (ml to m4) are involved in the generation of Ca 2+ oscillations in native mouse oocytes. ACh (10 μM) elicited regular Ca 2+ oscillations similar to those induced by sperm in their temporal characteristics. The Ca 2+ oscillations were abolished by application with atropine, the mAChR inhibitor. Within 1 min after treatment of ACh, intracellular Fluo-3 fluorescence intensity increased from 794±119 to 2023±755 (increase to 250% of original value), indicating a strong rise of cytosolic Ca 2+ concentration. 4-DAMP mustard and Tropicamide, specific antagonists of m3AChR and m4AChR, completely abolished ACh-induced Ca 2+ oscillations. In the ovulated oocytes, the expression of m3/m4 AChR was clearly detected by RT-PCR analysis. Furthermore, ACh-induced Ca 2+ oscillations were also abolished or decreased by PLC inhibitors (U73122 or D609) and an InsP 3 -receptor antagonist (xestospongin C), confirming that ACh generates Ca 2+ oscillations via the PLC-InsP 3 (PI) pathway. These results strongly suggest that m3/m4AChR is coupled to the generation of Ca 2+ oscillations mainly via the PI pathway in mouse oocytes.

Original languageEnglish
Pages (from-to)321-327
Number of pages7
JournalPflugers Archiv European Journal of Physiology
Volume447
Issue number3
DOIs
Publication statusPublished - 2003 Dec 1
Externally publishedYes

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Keywords

  • ACh
  • Ca oscillations
  • InsP
  • m3AChR
  • Muscarinic ACh receptor
  • PLC

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)

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