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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4 Pt 1
pubmed:dateCreated
1995-11-28
pubmed:abstractText
The purpose of the present study was to examine the role of adenosine triphosphate-sensitive potassium channels in mediating the coronary hyperemic response after crystalloid cardioplegia. Thirteen pigs were placed on normothermic cardiopulmonary bypass support. Hearts were arrested with cold (4 degrees C) crystalloid ([K+] 25 mmol/L) cardioplegic solution for 60 minutes. In seven of these pigs, hearts were then reperfused for 60 minutes with warm blood, and the animal was separated from cardiopulmonary bypass. The in vivo responses to the intracoronary administration of the K+ adenosine triphosphate channel blocker glibenclamide (50 gm/kg per minute) or the K+ adenosine triphosphate channel opener pinacidil (2 gm/kg per minute) were evaluated before cardiopulmonary bypass (baseline) and after 2 minutes and 60 minutes of reperfusion in the cardioplegia-reperfusion group. Under baseline conditions, glibenclamide and pinacidil induced a respective decrease and increase in coronary blood flow and an increase and a decrease in coronary vascular resistance. Coronary responses to glibenclamide and pinacidil were markedly enhanced after 2 minutes or 60 minutes of postcardioplegia reperfusion. In vitro responses of coronary arterioles (90 to 180 microns) were examined in a pressurized, no-flow state with video microscopy. The contractile response of coronary arterioles to glibenclamide and the relaxation response to pinacidil were significantly enhanced 2 minutes or 60 minutes after reperfusion (all p < 0.05 versus control). The response to pinacidil was markedly inhibited by glibenclamide, which confirms these antagonistic effects on K+ adenosine triphosphate channels. Decreased tissue concentrations of adenosine triphosphate in the coronary arterial smooth muscle and myocardium were observed after cardioplegia and persisted for up to 60 minutes of reperfusion (both p < 0.05 versus control). These results suggest that coronary hyperemia associated with postischemic cardioplegia is mediated in part by activation of K+ adenosine triphosphate channels in the coronary microcirculation.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-5223
pubmed:author
pubmed:issnType
Print
pubmed:volume
110
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1073-82
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Adenosine triphosphate-sensitive K+ channels mediate postcardioplegia coronary hyperemia.
pubmed:affiliation
Department of Surgery, Beth Israel Hospital, Boston, Mass. 02215, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't