Linked Life Data

10816603

Source:http://linkedlifedata.com/resource/pubmed/id/10816603

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2000-7-20
pubmed:abstractText
Signaling by two classes of endoplasmic reticulum (ER) Ca(2+) stores was studied in primary cultured rat astrocytes. Cytosolic and intra-ER Ca(2+) concentrations ([Ca(2+)](CYT) and [Ca(2+)](ER)) were measured with, respectively, Fura-2 and Furaptra, in separate experiments. The agonists, glutamate and ATP, released Ca(2+) primarily from cyclopiazonic acid (CPA)-sensitive ER Ca(2+) stores (CPA inhibits ER Ca(2+) pumps). Agonist-evoked release was abolished by prior treatment with CPA but was unaffected by prior depletion of caffeine/ryanodine (CAF/RY)-sensitive ER Ca(2+) stores. Conversely, prior depletion of the CPA-sensitive stores did not interfere with Ca(2+) release or reuptake in the CAF/RY-sensitive stores. Unloading of the CPA-sensitive stores, but not the CAF/RY-sensitive stores, promoted Ca(2+) entry through "store-operated channels." Resting [Ca(2+)](ER) averaged 153 microM (based on in situ calibration of Furaptra: K(D) = 76 microM, vs 53 microM in solution). The releasable Ca(2+) in both types of ER Ca(2+) stores was increased by Na(+) pump inhibition with 1 mM ouabain or K(+)-free medium. Using high spatial resolution imaging and image subtraction methods, we observed that some regions of the ER (45-58% of the total ER) unloaded and refilled when CPA was added and removed. Other regions of the ER (24-38%) unloaded and refilled when CAF was added and removed. The overlap between these two classes of ER was only 10-18%. These data indicate that there are two structurally separate, independent components of the ER and that they are responsible for the functional independence of the CPA-sensitive and CAF/RY-sensitive ER Ca(2+) stores.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0894-1491
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15-28
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Unloading and refilling of two classes of spatially resolved endoplasmic reticulum Ca(2+) stores in astrocytes.
pubmed:affiliation
Department of Physiology, University of Maryland School of Medicine, Baltimore 21201, USA. vgolovin@umaryland.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't