Linked Life Data

1688928

Source:http://linkedlifedata.com/resource/pubmed/id/1688928

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1990-3-6
pubmed:abstractText
The concentration dependence and kinetics of ionic currents activated by extracellular adenosine 5'-triphosphate (ATP) were studied in voltage-clamped dorsal root ganglion neurons from rats and bullfrogs. About 40% of neurons of both species responded to ATP with an increase in membrane conductance. The ATP-activated currents were similar in the 2 species, except that currents in rat neurons desensitized faster. In bullfrog neurons, the conductance was half-maximally activated by about 3 microM ATP; at low concentrations, the conductance increased 3- to 7-fold for a doubling in [ATP], suggesting that several ATP molecules must bind in order to activate the current. A steeper concentration-response relationship than expected from 1:1 binding was also seen in rat neurons. The current activated quickly upon application of ATP and decayed quickly when ATP was removed. Activation kinetics were faster at higher [ATP], with time constants decreasing from about 200 msec at 0.3 microM ATP to about 10 msec at 100 microM ATP. Deactivation kinetics (tau approximately 100-200 msec) were independent of the ATP concentration. The rapid activation and deactivation make it seem likely that the ATP-activated current is mediated by direct ligand binding rather than by a second-messenger system. The experimental observations can be mimicked by a simple model in which ATP must bind to 3 identical, noninteracting sites in order to activate a channel. The potency and kinetics of ATP action were voltage-dependent, with hyperpolarization slowing deactivation and increasing ATP's potency. Deactivation kinetics were also sensitive to the concentration of external Ca, becoming faster in higher Ca.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:volume
10
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1-10
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
ATP-activated channels in rat and bullfrog sensory neurons: concentration dependence and kinetics.
pubmed:affiliation
Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't