Linked Life Data

2881676

Source:http://linkedlifedata.com/resource/pubmed/id/2881676

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1987-5-12
pubmed:abstractText
In the presence of calcium, Ba2+ ions, at concentrations as low as 1-2 mM, block the action potentials (a.p.'s) elicited by the electrical stimulation of the primary spines of Diadema antillarum. Lower concentrations of barium (0.1 mM) potentiate the a.p.'s recorded from spines equilibrated with Ca-Free artificial sea water (ASW). Exposure of the spines to a saturated solution of EDTA in Ca-free, unbuffered ASW reversibly blocks their electrical activity. Spines blocked by EDTA continue to generate a.p.'s following their equilibration with Ca-free ASW containing 1 mM of Ba2+ ions. The time course of the a.p.'s recorded from spines equilibrated with normal ASW is only slightly affected by the combined action of 15 mM of tetraethylammonium (TEA) and 5 mM of 4-aminopyridine (4-AP). In contrast, the duration of the a.p.'s recorded from spines blocked by EDTA and placed in 1 mM barium is markedly increased by the combined actions of TEA and 4-AP at the above concentrations. We conclude that the Ca-channels of the neurites present in Diadema spines are not, at least qualitatively, an exception with regard to their permeation by Ba2+. The blocking action of low concentrations of these ions, particularly in the presence of calcium, may be explained by the extremely high surface to volume ratio prevailing in neurites with a diameter of only less than 0.1-0.3 micron.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0300-9629
pubmed:author
pubmed:issnType
Print
pubmed:volume
86
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
355-9
pubmed:dateRevised
2008-10-30
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Barium spikes are generated in the spines of the sea urchin Diadema antillarum.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.