Role of Hydrogen Sulfide and Oxidative Stress in Methamphetamine-Induced Cardiac Arrhythmias

心血管疾病，特别是心源性猝死是甲基苯丙胺(冰毒)使用者最常见的死亡原因，但确切的机制尚不清楚。在这项建议中，使用一种新的小动物电生理学建立的初步数据显示，在小鼠体内注射冰毒降低了房室硫化氢(H2S)水平，并增加了可诱发的房性和室性心律失常。这项提议检验了一种假设，即冰毒通过改变硫化氢的产生来增加心脏中活性氧的产生，导致心脏心房和心室的结构和电重构，从而导致房性和室性心律失常。为了实现这一长期目标，将通过分析冰毒注射的胱硫醚γ裂解酶转基因小鼠和补充硫化物的野生型(WT)小鼠与WT小鼠的心律失常表型、动作电位持续时间和纤维化，来评估硫化氢在冰毒相关的电和结构重构中的作用。此外，将通过测量冰毒和生理盐水处理的小鼠心房和心室中的组织和线粒体超氧化物水平，以及通过测量冰毒对氧化应激抑制的药物和遗传模型小鼠的心律失常表型和结构和电重构的影响，来评估氧化应激在冰毒相关的心脏电和结构重构中的作用。此外，将通过检测冰毒和生理盐水处理的WT小鼠、CSE-TG小鼠以及氧化应激抑制的药理学和遗传学模型小鼠心脏组织中磷酸化和氧化的CaMKII和RyR2来评估钙调蛋白激酶II(CaMKII)和RyR2在冰毒诱导的氧化应激介导的心律失常中的作用。最后，将通过将心律失常与硫化氢水平以及冰毒和生理盐水处理的WT和CSE TG小鼠的行为测试得分相关联，来评估冰毒使用、生成儿茶酚胺水平、硫化氢生物利用度、氧化应激、心理和认知功能障碍以及心律失常之间的关系。

Cardiovascular disease, specifically sudden cardiac death represents the most common cause of death among methamphetamine (METH) users but precise mechanism is unknown. Preliminary data in this proposal using a novel small animal electrophysiology set up shows that METH infusion in mice decreases atrial and ventricular hydrogen sulfide (H2S) levels and increases inducible atrial and ventricular arrhythmias. This proposal tests the hypothesis that METH use enhances reactive oxygen species production in the heart through altered H2S production, resulting in structural and electrical remodeling in the atria and ventricles of the heart leading to atrial and ventricular arrhythmias. To achieve this long-term objective, the role of H2S in METH associated electrical and structural remodeling in the heart will be evaluated by analyzing arrhythmia phenotype, action potential duration and fibrosis in METH infused Cystathionine γ-lyase (CSE, the predominant enzyme responsible for H2S production in mammals)transgenic mice and wild type (WT) mice supplemented with sulfide, compared to WT mice. In addition, the effect of oxidative stress in METH-associated electrical and structural remodeling in the heart will be assessed by measuring tissue and mitochondrial super-oxide levels in the atria and ventricles of METH and saline treated mice and by measuring the effect of METH on the arrhythmia phenotype and structural and electrical remodeling in pharmacological and genetic mouse models of oxidant stress inhibition. Furthermore, the role of calcium calmodulin kinase II (CaMKII) and Ryanodine receptor (RyR2) on METH induced oxidative stress mediated cardiac arrhythmias will be evaluated by measuring phosphorylated and oxidized CaMKII and RyR2 in the heart tissue of METH and saline treated WT mice, CSE-Tg mice and pharmacological and genetic mouse models of oxidant stress inhibition. Finally, the relationship between METH use, resultant catecholamine levels, H2S bioavailability, oxidative stress, psychological and cognitive dysfunction and cardiac arrhythmias will be evaluated by correlating cardiac arrhythmias to H2S levels, and scores on behavioral tests in METH and saline treated WT and CSE Tg mice.