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）使用者中最常见的死亡原因，但确切的机制尚不清楚。本研究使用一种新型小动物电生理装置的初步数据显示，冰毒输注小鼠可降低心房和心室硫化氢（H2S）水平，并增加诱发性心房和室性心律失常。该建议验证了甲基安非他明的使用通过改变H2S的产生来增强心脏活性氧的产生，从而导致心房和心室的结构和电重构，从而导致心房和室性心律失常的假设。为了实现这一长期目标，将通过分析甲基安非他明注入半胱硫氨酸γ-裂解酶（CSE，哺乳动物中主要负责产生H2S的酶）转基因小鼠和添加硫化物的野生型（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H2S在甲基安非他明相关的心脏电和结构重塑中的作用。此外，通过测量甲基安非他明和生理盐水处理小鼠心房和心室组织和线粒体超氧化物水平，以及测量甲基安非他明对氧化应激抑制小鼠药理学和遗传模型中心律失常表型和结构和电重构的影响，将评估氧化应激对甲基安非他明相关的心脏电和结构重构的影响。此外，通过测量甲基安非他明和生理盐水处理的WT小鼠、CSE-Tg小鼠以及氧化应激抑制小鼠的药理学和遗传模型中磷酸化和氧化的CaMKII和RyR2，我们将评估钙钙调素激酶II （CaMKII）和Ryanodine受体（RyR2）在甲基安非他明诱导的氧化应激介导的心律失常中的作用。最后，在冰毒和生理盐水处理的WT和CSE Tg小鼠中，通过将心律失常与H2S水平和行为测试分数相关联，评估冰毒使用、由此产生的儿茶酚胺水平、H2S生物利用度、氧化应激、心理和认知功能障碍与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.