Stretch-Activated Ion Channel Blocker Gadolinium Attenuates Ischemic ST-Segment Elevation in Canine Myocardium

概要

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Regional transmural ischemia causes both ST-segment elevation and systolic elongation(bulging)of the myocardium. Mechanical stretch might alter the transmembrane potentioal via stretch-activated ion channels(SAC); however, the role of SAC on ischemic ST-segment elevation has not yet fully studied. The present study investigated the role of SAC in the genesis of ischemic ST-segment elevation in the in-vivo canine heart. In 6 anesthetized dogs, an extracorporeal conduit connected to the left anterior descending coronary artery was occluded for 5 min before and after the intracoronary infusion of gadolinium(Gd, 500 μ mol/min). To eliminate the effect of ischemic preconditioning, the bypass was occluded for 5 min before the experiment. Percent systolic shortening(%SS)and percent systolic elongation(%bulging)were measured using a pair of ultrasonic dimension crystals. A unipolar epicardial ECG was monitored at the center of the ischemic area for the measurement of the ST-segment level. At the end of coronary occlusion, there was no difference in the reduction of %SS or the increase of %bulging between before and after infusion of Gd. ST-segment elevation, however, was significantly attenuated by the infusion of Gd. These data demonstrated that the activation of SAC is one cause of ischemic ST-segment elevation.
社団法人日本循環器学会の論文
1999-07-20