Lemmer B, Lang P H
Pol J Pharmacol Pharm. 1984 Mar-Jun;36(2-3):275-80.
Receptor binding studies with 3H-dihydroalprenolol (3H-DHA, spec. act. 90-102 Ci/mmol) were performed in heart ventricular membranes of light-dark-synchronized (L: 7-19 h, D: 19-7 h) male rats, which were sacrificed either at 08:00 h or 20:00 h. Saturation, competition and kinetic studies revealed two specific 3H-DHA binding sites--being specific for mainly beta 1-adrenoceptors--which were abolished after addition of the guanine nucleotide Gpp(NH)p. In control experiments, i.e. in the absence of the guanine nucleotide, circadian-phase-dependent differences in the KD and Bmax values were observed. Total number of binding sites was about 40% higher in the 20:00 h-ventricles than in the 08:00 h-ventricles. Pretreatment with isoprenaline further decreased and catecholamine-depletion further increased Bmax values. In accordance with these findings a significant circadian rhythm in the ventricular cAMP content with a maximum at 20:00 h and a minimum at 08:00 h was observed.
采用³H-二氢阿普洛尔（³H-DHA，比活度90 - 102 Ci/mmol）对光暗同步（光照时间：7 - 19时，黑暗时间：19 - 7时）的雄性大鼠心室膜进行受体结合研究，这些大鼠于08:00或20:00处死。饱和、竞争和动力学研究揭示了两个特异性³H-DHA结合位点——主要对β1-肾上腺素能受体具有特异性——在加入鸟嘌呤核苷酸Gpp(NH)p后消失。在对照实验中，即在无鸟嘌呤核苷酸的情况下，观察到KD和Bmax值存在昼夜节律依赖性差异。20:00处死的心室结合位点总数比08:00处死的心室高约40%。异丙肾上腺素预处理进一步降低Bmax值，而儿茶酚胺耗竭则进一步升高Bmax值。与这些发现一致，观察到心室cAMP含量存在显著的昼夜节律，在20:00达到最大值，在08:00达到最小值。
