培养的大鼠主动脉平滑肌细胞表达糖基化终产物受体和地尔硫Zh…

目的：探讨培养的主动脉平滑肌细胞（ＡＳＭＣ）上是否表达糖基化终产物（ＡＧＥＰ）高亲性受体和地尔硫Ｚｈｕｏ对ＡＧＥＰ升高胞浆游离钙的抑制。方法：用放射配基结合方法研究ＡＳＭＣ与ＡＧＥＰ的相互作用；用钙离子荧光指示剂Ｆｕｒａ２－ＡＭ测定ＡＳＭＣ胞浆游离钙。结果：ＡＳＭＣ上有ＡＧＥＰ高亲和性受体表达，其解离常数为６５．３±１．５ｍｏｌ·Ｌ＾－１，最大结合容量１．５７±０．０４ｎｍｏｌ／ｇ细胞蛋白；通过该

Expression of receptor for advanced glycosylation end products (AGEP) and inhibition of AGEP-induced cytosolic calcium elevation by diltiazem in cultured rat aortic smooth muscle cells.

AIM: To study whether there is a high affinity receptor for advanced glycosylation end product (AGEP) on thoracic aorta smooth muscle cells (ASMC) and to test effect of diltiazem on elevation of cytosolic free calcium induced by AGEP. METHODS: Interactions of AGEP-bovine serum albumin (BSA) with ASMC were studied with radioligand binding assay and cytosolic free calcium ([Ca2+]i) was examined in cultured ASMC with Fura 2-AM. RESULTS: AGEP-BSA was specifically bound to cells at 4 degrees C and was taken up and degraded at 37 degrees C. These processes were concentration-dependent and saturable. Scatchard analysis indicated that the receptor was with dissociation constant of 65.3 +/- 1.5 nmol.L-1 and its maximal binding capacity of 1.57 +/- 0.04 nmol/g cell protein. Early glycated low density lipoprotein (LDL) was not recognized by this receptor. AGEP-BSA elevated cytosolic free calcium in a concentration-dependent manner. Pretreatment with diltiazem inhibited AGEP-BSA-induced elevation in concentration- and time-dependent manners. CONCLUSION: There was a high affinity receptor for AGEP on ASMC, which mediated internalization and degradation of AGEP. Pretreatment with diltiazem inhibited the AGEP-induced elevation of cytosolic free calcium.