摘要
目的 为了证实人胚胎胸腺是否存在降黑素受体（ＭＲ）以及是否通过Ｇ蛋白介导的信息转导系统。方法 应用放射配体法测定中期引产人胎儿中枢性免疫器官——胸腺的ＭＲ。结果 它们具有高亲和力，平衡解离常数为（９．１±１．９） ｐｍｏｌ／Ｌ，低结合容量，蛋白的最大结合容量为（０．７４±０．２８） ｆｍ ｏｌ／ｍｇ；动力学研究显示具可逆性及可饱和性；特异性研究表明对降黑素（Ｍ）及其激动剂具高度特异性，符合特异结合位点的全部条件，而Ｇ蛋白抑制剂（ＧＴＰｒＳ）使［１２５Ｉ］Ｍ 特异结合位点量明显降低。结论 人类免疫器官是Ｍ 作用的靶器官，Ｍ 对免疫系统的作用应该是直接的，ＭＲ属于Ｇ蛋白系统。
Objective In order to verify the existing melatonin receptor in human embryo thymus and GTP rS effect on [ 125 I] iodomelatonin binding in human embryo thymus. Methods Specific binding of melatonin to embryo thymus was measured by using radioligand binding assays. Results Results revealed the maximum binding capacity (Bmax) was(0 94±0 28)fmol/mg protein and equilibrium constant (Kd) was (39 1±4 9) pmol/L.GTP rS dose dependently inhibited the binding. Conclusions These data demonstrated that specific binding of melatonin was present in the human embryo thymus.GTP rS inhibited the binding indicated that these putative melatonin receptors had coupled to G proteins.
出处
《中国神经免疫学和神经病学杂志》
CAS
1999年第4期224-228,共5页
Chinese Journal of Neuroimmunology and Neurology
