Linked Life Data

2546937

Source:http://linkedlifedata.com/resource/pubmed/id/2546937

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
1989-9-7
pubmed:abstractText
Measurement of fura-2 fluorescence and 45Ca2+ uptake was used to evaluate Ca2+ influx in cultured bovine aortic endothelial cells (BAECs) stimulated by bradykinin (BK). The BK-stimulated influx pathway was characterized with respect to its 1) sensitivity to extracellular Ca2+, 2) inhibition by membrane depolarization, and 3) permeability to Ba2+ and Sr2+. The results indicate that the activity of the influx pathway is a saturable function of extracellular Ca2+ and that membrane depolarization inhibits Ca2+ influx by changing the apparent affinity and maximal capacity of the pathway for Ca2+. Fura-2 fluorescence was used to compare the profiles for BK-stimulated changes in cytosolic Ca2+, Sr2+, and Ba2+ (Ca2+i, Ba2+i, and Sr2+i). Addition of Ca2+ and Sr2+ to Ca2+-depleted cells in the presence of BK produced a transient increase in Ca2+i and Sr2+i. Following the peak of the response, Ca2+i and Sr2+i declined within 2 min to a steady elevated level. Blockade of influx by the addition of La3+ at the peak of the response to Ca2+ and Sr2+ immediately reduced Ca2+i and Sr2+i to basal levels. Addition of Ba2+ to Ca2+-depleted cells in the presence of BK produced an increase in Ba2+i which continued to rise with time to a steady level. Addition of La3+ after Ba2+, however, did not reduce Ba2+i. These results suggest that 1) Ca2+ and Sr2+ (but not Ba2+) are sequestered by intracellular mechanisms and that the declining phase of the Ca2+ and Sr2+ response reflects a time and divalent cation-dependent inactivation of the influx pathway. The inactivation of the influx pathway was further demonstrated by measuring the kinetics of BK-stimulated 45Ca2+ uptake into BAECs. The results of these experiments demonstrate that BK stimulates a 100- to 150-fold increase in Ca2+ permeability of the BAEC but that the influx pathway turns off or inactivates within 2 min. The magnitude of the flux, the voltage sensitivity, and the ability to conduct Ca2+, Sr2+, and Ba2+ are suggestive of a channel mechanism.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
264
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12838-48
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Characterization of the bradykinin-stimulated calcium influx pathway of cultured vascular endothelial cells. Saturability, selectivity, and kinetics.
pubmed:affiliation
Department of Physiology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't