PMID- 7736564
OWN - NLM
STAT- MEDLINE
DCOM- 19950608
LR  - 20191210
IS  - 0143-4160 (Print)
IS  - 0143-4160 (Linking)
VI  - 17
IP  - 2
DP  - 1995 Feb
TI  - Thapsigargin induces cytoplasmic free Ca2+ oscillations in mouse oocytes.
PG  - 154-64
AB  - The mechanisms of calcium signalling in mammalian oocytes during maturation and 
      fertilization are controversial. In this study we measured intracellular free 
      Ca2+ concentrations ([Ca2+]i) with the photoprotein aequorin microinjected into 
      immature mouse oocytes. Immature mouse oocytes typically produced [Ca2+]i 
      responses to muscarinic acetylcholine (ACh) stimulation with two types of 
      component. The first component consisted of a broad transient rise in [Ca2+]i 
      lasting about 1 min. The second component consisted of pulsatile oscillations 
      which could occur before, during or after the broad transient, but typically 
      occurred on the rising phase of the broad transient, with a duration of about 5 
      s. Removal of external Ca2+ ([Ca2+]o) abolished the Ca2+ responses to ACh. 
      Exposure of oocytes to the specific microsomal Ca(2+)-ATPase inhibitors 
      thapsigargin (TG) and cyclopiazonic acid unexpectedly produced sustained 
      oscillations in [Ca2+]i which were sensitive to the concentration of Ca2+ in the 
      external milieu. The frequency of these oscillations was slow, and ceased, 
      sometimes after several cycles, when Ca2+o was removed. Raised [Ca2+]o 
      significantly increased the frequency in cells oscillating to TG and stimulated 
      nonoscillating cells to begin oscillating. The majority of responsive oocytes 
      which did not produce oscillations to ACh alone (70%), did so after TG treatment. 
      Detailed data analysis indicated that these oscillations were identical to those 
      generated by TG alone, with a similar sensitivity to changes in [Ca2+]o. Exposure 
      of oocytes to ryanodine did not inhibit oscillatory behaviour. These results 
      suggest that immature mouse oocytes possess a store which is insensitive to both 
      TG and ryanodine and is capable of supporting [Ca2+]i oscillations.
FAU - Lawrence, Y M
AU  - Lawrence YM
AD  - Department of Human Anatomy and Cell Biology, University of Liverpool, UK.
FAU - Cuthbertson, K S
AU  - Cuthbertson KS
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Netherlands
TA  - Cell Calcium
JT  - Cell calcium
JID - 8006226
RN  - 0 (Indoles)
RN  - 0 (Receptors, Muscarinic)
RN  - 0 (Terpenes)
RN  - 50934-79-7 (Aequorin)
RN  - 67526-95-8 (Thapsigargin)
RN  - EC 7.2.2.10 (Calcium-Transporting ATPases)
RN  - N9YNS0M02X (Acetylcholine)
RN  - SY7Q814VUP (Calcium)
RN  - X9TLY4580Z (cyclopiazonic acid)
SB  - IM
MH  - Acetylcholine/pharmacology
MH  - Aequorin
MH  - Animals
MH  - Calcium/*metabolism
MH  - Calcium-Transporting ATPases/*antagonists & inhibitors
MH  - Indoles/pharmacology
MH  - Mice
MH  - Microinjections
MH  - Oocytes/drug effects/*physiology
MH  - *Periodicity
MH  - Receptors, Muscarinic/metabolism
MH  - Signal Transduction
MH  - Terpenes/*pharmacology
MH  - Thapsigargin
EDAT- 1995/02/01 00:00
MHDA- 1995/02/01 00:01
CRDT- 1995/02/01 00:00
PHST- 1995/02/01 00:00 [pubmed]
PHST- 1995/02/01 00:01 [medline]
PHST- 1995/02/01 00:00 [entrez]
AID - 0143-4160(95)90084-5 [pii]
AID - 10.1016/0143-4160(95)90084-5 [doi]
PST - ppublish
SO  - Cell Calcium. 1995 Feb;17(2):154-64. doi: 10.1016/0143-4160(95)90084-5.