牛磺酸与硫酸镁联合用药的研究（Ⅱ）──对缺血／再灌心肌^（45）Ca内流及cAMP含量的影响

Effects of taurine alone and in combination with magnesium sulfate on￣(45) Ca influx and content of cAMP in ischemia/reperfusion myocardium

采用同位素示踪法及竞争性蛋白结合法，测试大鼠心肌缺血１０ｍｉｎ再灌３０ｓ４５Ｃａ内流和ｃＡＭＰ含量变化，并研究其与缺血／再灌心律失常的发生和牛磺酸（Ｔａｕｒ）、硫酸镁（ＭｇＳＯ４）抗缺血／再灌心律失常作用与心肌４５Ｃａ内流和ｃＡＭＰ含量的关系。结果表明，缺血／再灌心肌４５Ｃａ内流明显高于正常和缺血心肌。Ｔａｕｒ、ＭｇＳＯ４单用及合用均能降低缺血／再灌心律失常发生率和抑制心肌４５Ｃａ内流，两药合用作用更为明显。心肌缺血１０ｍｉｎ再灌３０ｓ心肌中ｃＡＭＰ含量则未见变化，Ｔａｕｒ、ＭｇＳＯ４对其亦无影响。证实两药抗缺血／再灌心律失常机制与抑制Ｃａ２＋内流、防止＂钙超负荷＂有关。

The relationship between ischemia/reperfusion arrhythmias and change of 45Ca influx or myocardial content of cAMP was studied In anesthetized rats. The effect of Taurine (Taur) alone and in combination with magnesium sulfate (MgSO4) on ischemia/reperfusion 45Ca influx and content of cAMP of cAMP in myocardium were also investigated. The results showed that in control group after reperfusion the 45Ca influx in myocardium was increased significantly. This effect was inhibited by pretreatment with Taur (50 mg·kg-1),MgSO4 (25 mg· kg-1)and combination of both agents. This study showed also that reperfusion did not increas myocardial content of cAMP. Taur or MgSO4 did not influence the myocardial content of cAMP in ischemia/reperfusion arrhythmic rats. These findings indicated that development of ischemia/reperfusion arrhythmia was related with the intracellular Ca2+ overload. Taur. MgSO4 were more effect on reperfusion arrhythmia. The mechanism of antiarrhythmic effect of Taur and MgSO4 may be involved in the inhibition of Ca2+ influx.