MYOCARDIAL PROTEIN KINASE C & B-ADRENOCEPTORS IN CHF

蛋白激酶C，一种依赖钙和磷脂的蛋白质 磷酸化酶存在于心肌中，已被证明 最近通过以下方法诱导心脏β-肾上腺素能脱敏 β肾上腺素能受体的磷酸化。来研究激活是否 蛋白激酶C的活性与心脏β-肾上腺素能 充血性心力衰竭的脱敏治疗，我们建议1) 比较心肌肌膜蛋白的数量和/或活性 心力衰竭和假手术犬中的激酶C，2)至 蛋白激酶C催化的肌动蛋白磷酸化特征 心脏心肌中的内源性底物蛋白 失败和假手术犬，3)研究 蛋白激酶C介导的细胞内充血性心力衰竭 使用分离的心肌细胞制剂在体外发挥功能，4) 确定蛋白激酶C的变化是否只发生在 压力超负荷的右室(特定于室壁)或者它们 也在左心室和循环中的淋巴细胞中发现，以及 5)研究蛋白激酶C在体内的抑制作用 使心肌β受体密度、腺苷环化酶正常化 心衰犬的活动性和β-肾上腺素能反应性。 三尖瓣将导致充血性右心衰竭 犬的撕脱和进行性肺动脉收缩。 将进行血流动力学测量，以确定程度 在动物被牺牲之前发生心力衰竭。本征 右侧的收缩功能和变力反应 将使用分离的右脑研究脑室到β-激动剂的关系 心室乳头肌准备。将采集样本 从右和左心室测量(~3H)-佛波醇- 12，13-二丁酸结合、蛋白激酶C活性、蛋白激酶 C-催化内源底物蛋白的磷酸化，β- 受体密度和腺苷环化酶活性。分离的心肌细胞 这些制剂将用于研究蛋白激酶的作用。 充血性心力衰竭对细胞内钙离子浓度的影响 氢和钙浓度，使用荧光指示器 和荧光分光光度法。这项研究结合了生理学、 清醒动物模型中的生化和细胞测量。 这一综合研究不仅将加深我们对 导致这种减少的基本细胞机制 充血性心力衰竭患者心脏对交感神经刺激的敏感性 心力衰竭，也可能为我们提供一种新的治疗方式 充血性心力衰竭的治疗。

Protein kinase C, a Ca2+- and phospholipid-dependent protein phosphorylation enzyme present in myocardium, has been shown recently to induce cardiac beta-adrenergic desensitization by phosphorylation of beta-adrenoceptors. To study whether activation of protein kinase C is responsible for cardiac beta-adrenergic desensitization in congestive heart failure, we propose 1) to compare the number and/or activity of cardiac sarcolemmal protein kinase C in heart failure and sham-operated dogs, 2) to characterize the protein kinase C-catalyzed phosphorylation of endogenous substrate proteins in the myocardium of the heart failure and sham-operated dogs, 3) to study the effect of congestive heart failure on protein kinase C-mediated cellular functions in vitro, using isolated myocyte preparations, 4) to determine whether changes in protein kinase C occur only in the pressure-overloaded right ventricle (chamber-specific) or they are also found in the left ventricle and circulating lymphocytes, and 5) to study whether inhibition of protein kinase C in vivo normalizes myocardial beta-receptor density, adenylate cyclase activity and beta-adrenergic responsiveness in heart failure dogs. Congestive right heart failure will be produced by tricuspid avulsion and progressive pulmonary artery constriction in dogs. Hemodynamic measurements will be taken to characterize the degree of heart failure before the animals are sacrificed. Intrinsic contractile function and inotropic responsiveness of the right ventricle to beta-agonists will be studied, using an isolated right ventricular papillary muscle preparation. Samples will be taken from the right and left ventricles for measuring (3H)-phorbol- 12,13-dibutyrate binding, protein kinase C activity, protein kinase C-catalyze phosphorylation of endogenous substrate proteins, beta- receptor density and adenylate cyclase activity. Isolated myocyte preparations will be used to study the effects of protein kinase C as influenced by congestive heart failure on intracellular hydrogen and calcium concentrations, using fluorescent indicators and spectrofluorimetry. The study incorporates physiological, biochemical and cellular measurements in a conscious animal model. This integrative study will not only further our understanding of the fundamental cellular mechanisms responsible for the decreased sensitivity of the heart to sympathetic stimulation in congestive heart failure, but also may provide us a new modality for the treatment of congestive heart failure.