Linked Life Data

1722252

Source:http://linkedlifedata.com/resource/pubmed/id/1722252

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1992-2-7
pubmed:abstractText
There is strong evidence that cromakalim (BRL 34915) relaxes smooth muscle by opening cell membrane K+ channels. The aim of this study was to use relatively selective K+ channel blockers to investigate 1) the K+ channel type(s) opened by cromakalim in guinea pig detrusor and 2) the role of different K+ channel types in the control of basal tension. Cromakalim produced a concentration-related relaxation (IC50 = 0.50 +/- 0.03 microM, n = 42) of 15 mM K(+)-evoked mechanical activity. The ATP-sensitive K+ channel blocker glyburide (0.3-3 microM) antagonized the effects of cromakalim in an apparently competitive manner (pA2 = 6.76). Charybdotoxin and iberiatoxin (3-30 nM), blockers of the large conductance, Ca(++)-activated K+ channel, appeared to functionally antagonize cromakalim. Apamin (1 microM) and leiurotoxin I (0.3 microM), blockers of the small conductance, Ca(++)-activated K+ channel, and noxiustoxin (0.3 microM), a blocker of squid axon delayed rectifer K+ channels, all failed to antagonize cromakalim. Cumulative administration of charybdotoxin and iberiatoxin produced marked, concentration-related stimulation of mechanical activity per se whereas glyburide, noxiustoxin, apamin and leiurotoxin I had no effect. Apamin and leiurotoxin I did stimulate mechanical activity to a small extent when administered noncumulatively, however. The results suggest that cromakalim opens ATP-sensitive K+ channels in detrusor and suggest that cromakalim does not open CA(++)-activated K+ channels and noxiustoxin-sensitive, delayed rectifier K+ channels. The marked stimulatory effects of charybdotoxin and iberiatoxin per se suggest an important role for large conductance, Ca(++)-activated K+ channels in the control of basal tension and, presumably, membrane potential in detrusor smooth muscle cells.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
259
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1158-64
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Effects of K+ channel blockers and cromakalim (BRL 34915) on the mechanical activity of guinea pig detrusor smooth muscle.
pubmed:affiliation
Department of Pharmacology, ICI Americas Inc., Wilmington, Delaware.
pubmed:publicationType
Journal Article, In Vitro