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Ca2+ stores in the chick embryo retina cells
A J Cristóvão1, A N Capela, C M Carvalho
1Center for Neuroscience of Coimbra, University of Coimbra, Portugal. ajcristovao@gemini.ci.vc.pt
Cellular Signalling
|January 1, 1997
Summary
Chick embryo retina cells possess distinct calcium (Ca2+) stores, primarily the endoplasmic reticulum (ER) and mitochondria. Thapsigargin and arachidonic acid effectively release Ca2+ from these internal stores.
Area of Science:
- Cell Biology
- Neuroscience
- Biochemistry
Background:
- Intracellular calcium (Ca2+) signaling is crucial for various cellular processes in the nervous system.
- Understanding the distinct Ca2+ stores and their mobilization mechanisms in retinal cells is essential for comprehending visual development and function.
Purpose of the Study:
- To characterize the different intracellular calcium (Ca2+) stores in digitonin-permeabilized chick embryo retina cells.
- To identify the agents capable of releasing Ca2+ from these stores and quantify their respective capacities.
Main Methods:
- Utilized Fluo-3 potassium salt fluorescence to monitor free Ca2+ concentrations in real-time.
- Employed ATP-dependent Ca2+ accumulation followed by release induction using cyclic-ADP-ribose (cADPR), inositol trisphosphate (Ins(1,4,5)P3), thapsigargin (Th), ionomycin (Ion), CCCP/oligomycin (CCCP/Olig), and arachidonic acid (AA).
Main Results:
- Ins(1,4,5)P3 and cADPR did not mobilize Ca2+ from internal stores.
- Thapsigargin and arachidonic acid effectively released Ca2+.
- Identified four distinct Ca2+ stores: thapsigargin-sensitive (likely ER, 63.3%), CCCP/oligomycin-sensitive (likely mitochondrial, 14.1%), arachidonic acid-sensitive (8.2%), and ionomycin-sensitive.
- Quantified the relative capacities of the ER, mitochondrial, and AA-sensitive stores.
Conclusions:
- Chick embryo retina cells contain multiple, functionally distinct intracellular Ca2+ stores.
- The endoplasmic reticulum represents the largest Ca2+ store, followed by mitochondria.
- Specific agents like thapsigargin and arachidonic acid are key to releasing Ca2+ from these identified stores, highlighting differential mobilization pathways.