Cruz Caturla M, Masotti M, Brodde O E, Hjemdahl P, Velasquez D, Turá A, Crexells C
Cardiac Catheterization Unit, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
J Heart Lung Transplant. 1992 Nov-Dec;11(6):1059-65.
An increase in basal heart rate caused by a lack of vagal control and chronotropic supersensitivity to epinephrine has been shown in transplanted human hearts. Prejunctional and/or postjunctional origins for this supersensitivity have been suggested, the latter involving changes in the number of myocardial beta-adrenergic receptors or in the receptor adenylate cyclase system. To directly determine the time course of change, serial determinations were performed during the first 3 months after heart transplantation. The beta-adrenergic receptor density measured by iodine 125-labelled iodocyanopindolol binding in 61 endomyocardial biopsy specimens (a mean of 6.1 +/- 0.58 biopsies from each of 10 patients) showed great intraindividual and interindividual variability (56.6 +/- 6.8 fmol/mg protein) with no mean trend toward gradually changing receptor densities. Isoproterenol-stimulated adenylate cyclase activity measured in 33 biopsy specimens (a mean of 5.5 +/- 0.67 biopsy specimens from each of six patients) varied considerably (112.5 +/- 13.8 pmol cyclic adenosine monophosphate/mg protein/min), again with no definite tendency with regard to the development over time. The beta-adrenergic receptor densities showed no statistical correlation with the degree of rejection as assessed by histologic criteria and antimyosin ration. These results suggest that in the first 3 months after heart transplantation beta-adrenergic receptor density and adenylate cyclase responses to 10 mumol/L isoproterenol do not change and that beta-adrenergic receptor density in the transplanted myocardium does not seem to be affected by the degree of rejection.
移植的人类心脏中已显示出，由于缺乏迷走神经控制和对肾上腺素的变时性超敏反应，基础心率会增加。有人提出这种超敏反应的起源是节前和/或节后的，后者涉及心肌β-肾上腺素能受体数量或受体腺苷酸环化酶系统的变化。为了直接确定变化的时间进程，在心脏移植后的前3个月进行了系列测定。通过125碘标记的碘氰吲哚洛尔结合法在61个心内膜活检标本中测量的β-肾上腺素能受体密度（10名患者每人平均6.1±0.58次活检）显示出很大的个体内和个体间变异性（56.6±6.8 fmol/mg蛋白质），且受体密度没有逐渐变化的平均趋势。在33个活检标本中测量的异丙肾上腺素刺激的腺苷酸环化酶活性（6名患者每人平均5.5±0.67个活检标本）差异很大（112.5±13.8 pmol环磷酸腺苷/mg蛋白质/分钟），同样在随时间发展方面没有明确趋势。β-肾上腺素能受体密度与通过组织学标准和抗肌凝蛋白比率评估的排斥程度没有统计学相关性。这些结果表明，在心脏移植后的前3个月，β-肾上腺素能受体密度和对10μmol/L异丙肾上腺素的腺苷酸环化酶反应没有变化，并且移植心肌中的β-肾上腺素能受体密度似乎不受排斥程度的影响。
