Linked Life Data

21191818

Source:http://linkedlifedata.com/resource/pubmed/id/21191818

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2011-3-1
pubmed:abstractText
Ginsenosides, active ingredients of Panax ginseng, are known to exhibit neuroprotective effects. Large-conductance Ca(2+)-activated K(+) (BK(Ca)) channels are key modulators of cellular excitability of neurons and vascular smooth muscle cells. In the present study, we examined the effects of ginsenosides on rat brain BK(Ca) (rSlo) channel activity heterologously expressed in Xenopus oocytes to elucidate the molecular mechanisms how ginsenoside regulates the BK(Ca) channel activity. Ginsenoside Rg(3) (Rg(3)) enhanced outward BK(Ca) channel currents. The Rg(3)-enhancement of outward BK(Ca) channel currents was concentration-dependent, voltage-dependent, and reversible. The EC(50) was 15.1 ± 3.1 ?M. Rg(3) actions were not desensitized by repeated treatment. Tetraetylammonium (TEA), a K(+) channel blocker, inhibited BK(Ca) channel currents. We examined whether extracellular TEA treatment could alter the Rg(3) action and vice versa. TEA caused a rightward shift of the Rg(3) concentration-response curve (i.e., much higher concentration of Rg(3) is required for the activation of BK(Ca) channel compared to the absence of TEA), while Rg(3) caused a rightward shift of the TEA concentration-response curve in wild-type channels. Mutation of the extracellular TEA binding site Y360 to Y360I caused a rightward shift of the TEA concentration-response curve and almost abolished both the Rg(3) action and Rg(3)-induced rightward shift of TEA concentration-response curve. These results indicate that Tyr360 residue of BK(Ca) channel plays an important role in the Rg(3)-enhancement of BK(Ca) channel currents.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0219-1032
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
133-40
pubmed:meshHeading
pubmed-meshheading:21191818-Amino Acid Sequence, pubmed-meshheading:21191818-Amino Acid Substitution, pubmed-meshheading:21191818-Animals, pubmed-meshheading:21191818-Calcium, pubmed-meshheading:21191818-Ginsenosides, pubmed-meshheading:21191818-Intracellular Space, pubmed-meshheading:21191818-Ion Channel Gating, pubmed-meshheading:21191818-Large-Conductance Calcium-Activated Potassium Channels, pubmed-meshheading:21191818-Molecular Sequence Data, pubmed-meshheading:21191818-Mutant Proteins, pubmed-meshheading:21191818-Mutation, pubmed-meshheading:21191818-Oocytes, pubmed-meshheading:21191818-Patch-Clamp Techniques, pubmed-meshheading:21191818-Rats, pubmed-meshheading:21191818-Structure-Activity Relationship, pubmed-meshheading:21191818-Tetraethylammonium, pubmed-meshheading:21191818-Tyrosine, pubmed-meshheading:21191818-Xenopus
pubmed:year
2011
pubmed:articleTitle
Ginsenoside Rg3 enhances large conductance Ca2+-activated potassium channel currents: a role of Tyr360 residue.
pubmed:affiliation
Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul, Korea.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't