Linked Life Data

7714809

Source:http://linkedlifedata.com/resource/pubmed/id/7714809

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-5-17
pubmed:abstractText
The effect of adenosine on locus ceruleus neurons was investigated with intracellular recording in a totally submerged brain slice preparation. Bath application of adenosine (100 microM) hyperpolarized locus ceruleus neurons and inhibited their spontaneous firing; under voltage-clamp conditions, adenosine activated an inwardly rectifying, outward current (IAdo). The reversal potential of the IAdo was -110 mV and shifted by 59.2 mV per 10-fold change in external K+ concentration, very close to the shift predicted by the Nernst equation for a pure K+ current. The IAdo was due to a direct postsynaptic action, because it persisted in low Ca++/high Mg++ media that block Ca(++)-dependent neurotransmitter release. The IAdo was not blocked by glibenclamide, which indicates that it is not mediated by ATP-dependent K+ channels. The adenosine-activated current was concentration-dependent (10 microM-1 mM adenosine) and was blocked by the selective A1 antagonist 8-cyclopentyltheophylline in a competitive manner. Schild analysis in two neurons yielded estimates of the Kd value for 8-cyclopentyltheophylline of 1.4 and 4.6 nM, which indicates that the IAdo is mediated by A1 adenosine receptors. The adenosine-induced hyperpolarization, inhibition of firing and activation of outward current were blocked by external barium, but not by 4-aminopyridine. By contrast, we have previously shown that adenosine enhances A-current, thereby reducing action potential duration in locus ceruleus neurons, and these effects are blocked by 4-aminopyridine but not barium. These data indicate that the adenosine-induced hyperpolarization and inhibition of firing are mediated by the IAdo and that these effects are independent of adenosine's enhancement of A-current.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
537-44
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Characterization of the adenosine A1 receptor-activated potassium current in rat locus ceruleus neurons.
pubmed:affiliation
Department of Physiology and Biophysics, University of Illinois at Chicago, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.