COCAINE-INDUCED VENTRICULAR FIBRILLATION

可卡因的日益流行和广泛使用已经达到 流行比例。伴随着可卡因滥用增加的是 与可卡因有关的急诊室就诊人数上升， 入院和死亡人数。事实上，越来越多的证据表明 可卡因会引发致命的心血管事件，包括中风， 心肌梗死和恶性心律失常，如 室颤(VF)。尽管两国之间的联系日益密切 致命性心脏事件，对其机制知之甚少 引发这些心血管事件，特别是室颤。这很好 证实可卡因可以增强肾上腺素能刺激的效果 这反过来又会降低心脏的电稳定性。这个 增强的肾上腺素能活动促进室颤的机制不是 为人所知。最终，肾上腺素能受体的激活必须唤起各种 心脏组织中的细胞反应。这些内部的更改 心肌细胞对室性心动过速的发生有重要作用。它 因此，拟议的一系列实验的目的是：a) 研究可卡因对心脏电稳定性的影响；b) 确定可卡因诱导肾上腺素能活动增加的作用 在VF中发挥作用；c)确定可卡因的细胞内介质的作用 在室颤中发挥作用；以及d)研究可卡因对血流动力学的影响 特别强调肾上腺素能活动的增强会导致 细胞内钙的积累，从而增加易感性 到VF，将会受到考验。慢性可卡因使用和急性中毒的影响 对VF敏感性的停药也将进行调查。这个 运动、急性缺血和可卡因的组合已被证明 VF诱发率高，可作为可卡因诱导性VF的动物模型。 药物干预将用于研究肾上腺素能和 细胞内对室颤的贡献。预计一旦 可卡因诱发室颤的机制已经确定，新的 可以设计出治疗干预措施来减少这种情况的数量 过早死亡。

The increasing popularity and widespread use of cocaine has reached epidemic proportions. Accompanying the increase in cocaine abuse has been an escalation in the number of cocaine related emergency room visits, hospital admissions and deaths. Indeed, there is increasing evidence that cocaine can provoke lethal cardiovascular events including stroke, myocardial infarction, and malignant cardiac rhythm disorders such as ventricular fibrillation (VF). In spite of the growing association between lethal cardiac events, relatively little is known about the mechanisms precipitating these cardiovascular event, particularly VF. It is well established that cocaine can enhance the effects of adrenergic stimuli which are, in turn, known to reduce cardiac electrical stability. The mechanism by which enhanced adrenergic activity contributes to VF is not known. Ultimately activation of adrenergic receptors must evoke a variety of cellular responses in the cardiac tissue. These alterations within the cardiac cells could contribute significantly to the development of VF. It is therefore the purpose of the proposed series of experiments to: a) investigate the effects of cocaine on cardiac electrical stability; b) determine the role that cocaine-induced increases in adrenergic activity play in VF; c) determine the role that intracellular mediators of cocaine play in VF; and d) investigate the hemodynamic effects of cocaine with particular emphasis enhancement of adrenergic activity leads to the accumulation of cytosolic calcium, and thereby increases the susceptibility to VF, will be tested. The effects of chronic cocaine use and acute withdrawal on the sensitivity to VF will also be investigated. The combination of exercise, acute ischemia and cocaine has been shown to induce VF reliably and will serve an a model of cocaine-induced VF. Pharmacologic interventions will be used to investigate adrenergic and intracellular contributions to VF. It is anticipated that once the mechanisms responsible for cocaine-induced VF have been determined, novel therapeutic interventions can be devised to reduce the number of these untimely deaths.