Denniss A R, Colucci W S, Allen P D, Marsh J D
Department of Medicine, Brigham and Women's Hospital, Boston 02115.
J Mol Cell Cardiol. 1989 Jul;21(7):651-60. doi: 10.1016/0022-2828(89)90606-8.
This study examined the characteristics and distribution of sarcolemmal and light vesicular beta-adrenergic receptors (BAR) in left ventricular myocardium from 15 adults (aged 17 to 58 years) without left ventricular dysfunction or coronary artery disease and 29 patients (aged 14 to 53 years) with end-stage congestive heart failure (CHF). Sarcolemmal and intracellular fractions were prepared by 40,000 x g and 108,000 x g centrifugation, respectively. Agonist and antagonist binding properties were assessed by nonlinear computer modelling of isoproterenol-125I-pindolol (IPIN) displacement curves. Adenylate cyclase activity was also examined. Distribution of intracellular and sarcolemmal BAR was similar in normal and failing left ventricular myocardium, with intracellular BAR comprising 4.5 +/- 2.2% of total BAR in normal human heart and 5.7 +/- 5.1% of total BAR in CHF patients. For sarcolemmal BAR, antagonist affinity was similar for normal and CHF patients (KD IPIN in normals, 21.7 +/- 2.6 pM; KD IPIN in CHF, 20 +/- 2.3 pM). Agonist affinity was somewhat higher in CHF patients (KD isoproterenol in normals, 33 +/- 4.9 nM; KD isoproterenol in CHF, 6.2 +/- 1.5 nM). Sarcolemmal BAR number was reduced in CHF from 21.4 +/- 2.9 to 16.4 +/- 1.3 fmol/mg protein (P less than 0.04). Cyclic AMP production (pmol/mg protein/min above basal) was less in CHF after Gpp(NH)p stimulation (normals, 82 +/- 20; CHF, 27 +/- 9; P less than 0.01) and after stimulation with Gpp(NH)p + isoproterenol (normals, 129 +/- 25; CHF, 56 +/- 13; P less than 0.02). Stimulation with manganese + forskolin resulted in similar levels of cyclic AMP production in normals and in CHF patients. We conclude that: (a) sarcolemmal BAR number is reduced in CHF, but BAR are not redistributed intracellularly and (b) beta-adrenergic transmembrane signalling in CHF is also impaired at the level of the guanine nucleotide regulatory proteins.
本研究检测了15名无左心室功能障碍或冠状动脉疾病的成年人（年龄17至58岁）以及29名终末期充血性心力衰竭（CHF）患者（年龄14至53岁）左心室心肌中肌膜和轻囊泡β-肾上腺素能受体（BAR）的特征及分布。分别通过40,000×g和108,000×g离心制备肌膜和细胞内组分。通过对异丙肾上腺素-125I-吲哚洛尔（IPIN）置换曲线进行非线性计算机建模评估激动剂和拮抗剂的结合特性。同时也检测了腺苷酸环化酶活性。正常和衰竭的左心室心肌中细胞内和肌膜BAR的分布相似，细胞内BAR在正常人心肌中占总BAR的4.5±2.2%，在CHF患者中占总BAR的5.7±5.1%。对于肌膜BAR，正常人和CHF患者的拮抗剂亲和力相似（正常人中IPIN的KD为21.7±2.6 pM；CHF中IPIN的KD为20±2.3 pM）。CHF患者的激动剂亲和力略高（正常人中异丙肾上腺素的KD为33±4.9 nM；CHF中异丙肾上腺素的KD为6.2±1.5 nM）。CHF患者肌膜BAR数量从21.4±2.9 fmol/mg蛋白降至16.4±1.3 fmol/mg蛋白（P<0.04）。在Gpp(NH)p刺激后（正常人，82±20；CHF，27±9；P<0.01）以及在Gpp(NH)p+异丙肾上腺素刺激后（正常人，129±25；CHF，56±13；P<0.02），CHF患者的环磷酸腺苷生成（高于基础值的pmol/mg蛋白/分钟）较少。用锰+福斯高林刺激后，正常人和CHF患者的环磷酸腺苷生成水平相似。我们得出结论：（a）CHF患者肌膜BAR数量减少，但BAR在细胞内未重新分布；（b）CHF患者中β-肾上腺素能跨膜信号传导在鸟嘌呤核苷酸调节蛋白水平也受损。
