Effects of diltiazem and isoflurane on stunned rat heart / 中华麻醉学杂志

ABSTRACT

ve To investigate the effects of different doses of diltiazem alone or combination with isoflurane on stunned isolated rat heart. Methods Adult male Wistar rats weighing 325-350g were anesthetized with intraabdominal pentobarbital sodium 60mg?kg-1. Heparin 200IU was injected into femoral vein. Chest was then opened and heart was removed and connected to Langendorff preparation. The isolated rat heart was perfused at 100cm H2O with Krebs-Hensleit buffer(KHB) balanced with 95%O2 and 5%CO2 at 37℃ and electrically paced at 300 bpm. Global myocardial ischemia was produced by suspension of perfusion. The isolated rat heart underwent 20 min ischemia followed by 30min reperfusion. 40 rat hearts were randomly allocated to one of 5 groups of eight each, group Ⅰ received no treatment and served as control; group Ⅱ the isolated heart was perfused with 0.1/?mol?L-1 diltiazem for 10 min before the onset of ischemia; group Ⅲ with 0.5?mol?L-1 diltiazem; group Ⅳ with 0. 1?mol?L-1 diltiazem + 1.5MAC isoflurane; group Ⅴ with 0.5?mol?L-1 diltiazem + 1.5MAC isoflurane. Left ventricle developed pressure(DP) was measured from a fluid-filled Latex balloon placed in left ventricle. The volume of the fluid in the balloon was regulated to maintain the left ventricle end-diastolic pressure at 5-8 mm Hg. Peak systolic pressure(PSP), end-diastolic pressure(EDP) and developed pressure(DP) were measured after the isolated heart was stabilized for 10min (baseline value) and 5, 10, 15, 20, 25, 30min after reperfusion. Maximum intraventricular pressure was measured during ischemia when the isolated heart was not paced and at a stand still. Results There was no significant difference in DP, EDP, + dp/dtmax and - dp/dtmin after the isolated hearts were stabilized for 10min, before ischemia among the five groups. Perfusion with 0.1?mol?L-1 diltiazem did not affect DP significantly but 0.5?mol?L-1 diltiazem significantly decreased DP (P