Linked Life Data

11547543

Source:http://linkedlifedata.com/resource/pubmed/id/11547543

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2001-9-7
pubmed:abstractText
The effects of gymnochrome A were tested on the electrical activity of the frog atrial heart muscle. Gymnochrome A (1-5 microM) did not alter the resting potential. Gymnochrome A (5 microM) slowed the initial depolarizing phase of the spontaneously beating action potential. Under voltage-clamp conditions gymnochrome A (5 microM) did not affect the electrical constant of the membrane and the kinetic parameters of the peak Na+ current (INa) recorded in the Ringer solution containing tetraethylammonium (2 mM) and Cd2+ (1 mM) but shifted the membrane potential at which the current both activated and reached its maximal value toward more negative membrane potentials. It did not alter the reversal potential for INa, indicating that the selectivity of the Na+ channels had not changed. These observations suggest that gymnochrome A binds to the membrane and shifts the activation of INa on the voltage axis by modifying the free negative fixed charges present at the membrane surface rather than by occupying a specific site on the Na+ channel. Photoexcited gymnochrome A transiently triggered an early outward current which lengthened the time-to-peak of INa and decreased its amplitude. In addition, photoexcited gymnochrome A blocked the background K+ current. This is, to our knowledge, the first time that such effects are reported on the cardiac muscle. These observations suggest that the photoexcitation of gymnochrome produces physico-chemical effects which lead to intracellular changes. Further experiments are required to determine their nature.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0031-8655
pubmed:author
pubmed:issnType
Print
pubmed:volume
74
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
115-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Alterations of transmembrane currents in frog atrial heart muscle induced by photoexcited gymnochrome A purified from the crinoid, Gymnochrinus richeri.
pubmed:affiliation
Laboratoire d'Optique et Biosciences, INSERM U 451 UMR CNRS 7645/ENSTA, Ecole Polytechnique, Palaiseau, France. sauviat@polytechnique.fr
pubmed:publicationType
Journal Article, In Vitro