Ferry D R, Kaumann A J
Br J Pharmacol. 1987 Mar;90(3):447-57. doi: 10.1111/j.1476-5381.1987.tb11194.x.
The stoichiometric relationship between adrenoceptors and saturable binding sites for 1,4-dihydropyridines in calcium channels was investigated in human ventricular myocardium. Membrane particles were prepared from heart specimens of patients undergoing open heart surgery. The patients suffered from hypertrophic obstructive cardiomyopathy (HOCM) or mitral valve disease. Using [3H]-prazosin and [125I]-2-beta-hydroxy-3-iodiphenyl-ethyl-aminoethyl tetralone ([125I]-HEAT) as labels we detected only a marginal density of alpha 1-adrenoceptors, regardless of disease. No alpha 2-adrenoceptors were detected with [3H]-rauwolscine. In HOCM patients we estimated 72 +/- 10 fmol mg-1 (n = 12) beta-adrenoceptors labelled with [3H]-(-)-dihydroalprenolol and 74 +/- 5 fmol mg-1 (n = 2) beta-adrenoceptors labelled with [125I]-(-)-iodocyanopindolol; the equilibrium dissociation constants KD, were 1.2 +/- 0.2 nmol l-1 for [3H]-(-)-dihydroalprenolol and 7 +/- 1 pmol l-1 for [125I]-(-)-iodocyanopindolol. In patients with mitral valve disease we estimated 84 +/- 11 fmol mg-1 (n = 3) labelled with [3H]-(-)-dihydroalprenolol and 66 +/- 13 fmol mg-1 (n = 2) labelled with [125I]-(-)-iodocyanopindolol. The KD values were 1.8 +/- 0.6 nmol l-1 for [3H]-(-)-dihydroalprenolol and 8 +/- 2 pmol l-1 for [125I]-(-)-iodocyanopindolol. In 14 HOCM patients we estimated 107 +/- 12 fmol mg-1 calcium channel sites labelled with [3H]-nimodipine with a KD of 280 +/- 4 pmol l-1. In 5 patients with mitral valve disease the density of calcium channel sites labelled with [3H]-nimodipine was 78 +/- 5 fmol mg-1 with a KD of 290 +/- 20 pmol l-1, In HOCM patients the density of calcium channel sites labelled with the benzoxadiazol 1,4-dihydropyridine ([3H]-(+)-PN 200-110) was 1.6 fold of that labelled with [3H]-nimodipine with a KD of 84 +/- 11 pmol l-1. In a group of 4 HOCM patients in which calcium channels were labelled with [125I]-iodipine, the density of sites was 1.37 +/- 0.07 fold the density of sites labelled by [3H]-(+)-PN 200-11-. The KD value of [125I]-iodipine was 246 +/- 16 pmol-1. (+)-PN 200-110 was approximately 100 fold more potent than (-)-PN 200-110 as a competitor of [125I]-iodipine binding. For the HOCM group a significant correlation was found between beta-adrenoceptor density and calcium channel density, whereas in the mitral valve group no such correlation was found. This does not prove that there is causal interaction leading to a relationship between the density of beta-adrenoceptors and calcium channels. However, because positive inotropic effects of catecholamines mediated by beta-adrenoceptors are associated with opening of calcium channels, this suggests that the density of both beta-adrenoceptors and calcium channels could be co-regulated.
在人心室心肌中研究了肾上腺素能受体与钙通道中1,4 - 二氢吡啶可饱和结合位点之间的化学计量关系。膜颗粒取自接受心脏直视手术患者的心脏标本。这些患者患有肥厚性梗阻性心肌病（HOCM）或二尖瓣疾病。使用[³H] - 哌唑嗪和[¹²⁵I] - 2 - β - 羟基 - 3 - 碘二苯基 - 乙氨基乙基四氢萘酮（[¹²⁵I] - HEAT）作为标记物，我们检测到无论疾病情况如何，α₁ - 肾上腺素能受体的密度都仅处于边缘水平。用[³H] - 萝芙木碱未检测到α₂ - 肾上腺素能受体。在HOCM患者中，我们估计用[³H] - （ - ） - 二氢阿普洛尔标记的β - 肾上腺素能受体为72±10 fmol mg⁻¹（n = 12），用[¹²⁵I] - （ - ） - 碘氰吲哚洛尔标记的β - 肾上腺素能受体为74±5 fmol mg⁻¹（n = 2）；平衡解离常数KD，对于[³H] - （ - ） - 二氢阿普洛尔为1.2±0.2 nmol l⁻¹，对于[¹²⁵I] - （ - ） - 碘氰吲哚洛尔为7±1 pmol l⁻¹。在二尖瓣疾病患者中，我们估计用[³H] - （ - ） - 二氢阿普洛尔标记的为84±11 fmol mg⁻¹（n = 3），用[¹²⁵I] - （ - ） - 碘氰吲哚洛尔标记的为66±13 fmol mg⁻¹（n = 2）。KD值对于[³H] - （ - ） - 二氢阿普洛尔为1.8±0.6 nmol l⁻¹，对于[¹²⁵I] - （ - ） - 碘氰吲哚洛尔为8±2 pmol l⁻¹。在14例HOCM患者中，我们估计用[³H] - 尼莫地平标记的钙通道位点为107±12 fmol mg⁻¹，KD为280±4 pmol l⁻¹。在5例二尖瓣疾病患者中，用[³H] - 尼莫地平标记的钙通道位点密度为78±5 fmol mg⁻¹，KD为290±20 pmol l⁻¹。在HOCM患者中，用苯并恶二唑1,4 - 二氢吡啶（[³H] - (+) - PN 200 - 110）标记的钙通道位点密度是用[³H] - 尼莫地平标记的1.6倍，KD为84±11 pmol l⁻¹。在一组4例用[¹²⁵I] - 碘尼地平标记钙通道的HOCM患者中，位点密度是用[³H] - (+) - PN 200 - 11 - 标记位点密度的1.37±0.07倍。[¹²⁵I] - 碘尼地平的KD值为246±16 pmol⁻¹。(+) - PN 200 - 110作为[¹²⁵I] - 碘尼地平结合的竞争者，其效力比( - ) - PN 200 - 110约强100倍。对于HOCM组，发现β - 肾上腺素能受体密度与钙通道密度之间存在显著相关性，而在二尖瓣组中未发现这种相关性。这并未证明存在导致β - 肾上腺素能受体密度与钙通道之间关系的因果相互作用。然而，由于β - 肾上腺素能受体介导的儿茶酚胺正性肌力作用与钙通道开放有关，这表明β - 肾上腺素能受体和钙通道两者的密度可能共同受到调节。
