Carman-Krzan M, Lipnik-Stangelj M
Department of Pharmacology, Medical Faculty, Ljubljana, Slovenia.
Pflugers Arch. 2000;439(3 Suppl):R131-2.
We identified and characterised histamine H1 and H2 receptor subtypes on rat cortical astrocytes in primary culture with radioligand binding studies and compared their molecular properties with peripheral (bovine vascular smooth muscle and endothelial cells) histamine H1 and H2 receptors. Our results showed the existence of a homogenous population of high affinity binding sites for 3H-mepyramine (Bmax = 281 fmol/mg protein, K(D) = 3.5 +/- 0.7 nM) and 3H-tiotidine (Bmax = 59 fmol/mg protein, K(D) = 1.9 +/- 0.7 nM) on astrocytes, which was further confirmed by competition binding studies using various H1 and H2 specific agonists/antagonists. We showed differences in the density of receptors and differences in the affinities of competing drugs for the same histamine receptor subtype (H1 and H2) between the tissues used, which indicate different molecular properties of the central and peripheral histamine receptors.
我们通过放射性配体结合研究，在原代培养的大鼠皮质星形胶质细胞上鉴定并表征了组胺H1和H2受体亚型，并将它们的分子特性与外周（牛血管平滑肌和内皮细胞）组胺H1和H2受体进行了比较。我们的结果显示，星形胶质细胞上存在对3H-美吡拉敏（Bmax = 281 fmol/mg蛋白质，K(D) = 3.5 +/- 0.7 nM）和3H-替丁（Bmax = 59 fmol/mg蛋白质，K(D) = 1.9 +/- 0.7 nM）的高亲和力结合位点的同质群体，这通过使用各种H1和H2特异性激动剂/拮抗剂的竞争结合研究得到了进一步证实。我们发现所使用的组织之间，同一组胺受体亚型（H1和H2）的受体密度以及竞争药物的亲和力存在差异，这表明中枢和外周组胺受体具有不同的分子特性。
