Steinkraus V, Körner C, Steinfath M, Mensing H
Department of Dermatology, University of Hamburg, Federal Republic of Germany.
Arch Dermatol Res. 1991;283(5):328-32. doi: 10.1007/BF00376622.
A non-tumorigenic keratinocyte cell line with complete epidermal differentiation capacity (HaCaT) was used in radioligand binding experiments to determine the number of beta-adrenoceptors. Intact cells were saturated with 3H-labelled (-)CGP-12177 (CGP), a hydrophilic non-selective beta-adrenergic antagonist as radioligand. In order to investigate the beta-adrenergic subtype selectivity, displacement experiments were performed with different antagonists and agonists. Binding of CGP to keratinocytes has been shown to be reversible and saturable and to have high affinity (Bmax = 114.0 +/- 8.8 fmol/10(7) cells with 6866 receptors/cell, KD = 0.095 +/- 0.017 nmol/l; n = 11). Beta-adrenergic antagonists inhibited binding yielding monophasic displacement curves. IC50-values (nmol/l) were: propranolol (non-selective) 1.68; CGP-12177 (non-selective) 1.08; ICI 118,551 (beta 2-selective) 2.92; bisoprolol (beta 1-selective) 1230; and CGP-20712 (beta 1-selective) 24,980. Agonists displaced CGP in the order isoprenaline greater than adrenaline greater than noradrenaline. We conclude that HaCaT cells express a high density of beta2-adrenoceptors providing a good model system to study adrenergic receptor mechanisms under reproducible experimental conditions in keratinocytes.
一种具有完全表皮分化能力的非致瘤性角质形成细胞系（HaCaT）被用于放射性配体结合实验，以确定β-肾上腺素能受体的数量。完整细胞用3H标记的（-）CGP-12177（CGP）饱和，CGP是一种亲水性非选择性β-肾上腺素能拮抗剂，用作放射性配体。为了研究β-肾上腺素能亚型的选择性，用不同的拮抗剂和激动剂进行了置换实验。CGP与角质形成细胞的结合已被证明是可逆的、可饱和的，并且具有高亲和力（Bmax = 114.0 +/- 8.8 fmol/10(7) 个细胞，每细胞有6866个受体，KD = 0.095 +/- 0.017 nmol/l；n = 11）。β-肾上腺素能拮抗剂抑制结合，产生单相置换曲线。IC50值（nmol/l）分别为：普萘洛尔（非选择性）1.68；CGP-12177（非选择性）1.08；ICI 118,551（β2选择性）2.92；比索洛尔（β1选择性）1230；以及CGP-20712（β1选择性）24,980。激动剂置换CGP的顺序为异丙肾上腺素大于肾上腺素大于去甲肾上腺素。我们得出结论，HaCaT细胞表达高密度的β2-肾上腺素能受体，为在角质形成细胞中可重复的实验条件下研究肾上腺素能受体机制提供了一个良好的模型系统。
