α_1肾上腺素受体亚型在家兔胸主动脉平滑肌细胞生长中的作用

EFFECTS OF α_1-ADRENERGIC RECEPTOR SUBTYPES ACTIVATION ON PROLIFERATION OF SMOOTH MUSCLE CELLS IN RABBIT AORTA

本实验在体外培养的家兔胸主动脉平滑肌细胞上，利用３Ｈ－Ｔｈｙｍｉｄｉｎｅ（３Ｈ－ＴｄＲ）掺入的方法，观察了α１－肾上腺素受体（ａｄｒｅｎｅｒｇｉｃｒｅｃｅｐｔｏｒ，ＡＲ）及其亚型对平滑肌细胞ＤＮＡ合成的影响。结果显示：去甲肾上腺素激动α１－ＡＲ能促进平滑肌细胞ＤＮＡ合成，并有以下特点：（１）α１Ａ激动促进平滑肌细胞ＤＮＡ合成，但α１Ｂ激动抑制这一合成作用；（２）α１Ａ促进ＤＮＡ合成的作用与ｃ－ｆｏｓ基因表达有关；（３）α１－ＡＲ的促生长作用与神经肽Ｙ有协同作用，而与血管紧张素Ⅱ仅有相加的作用；（４）培养的平滑肌细胞上α１Ｂ有一定的固有活性，表现为抑制平滑肌细胞ＤＮＡ合成。

The effect of α1-Adrenoceptor (α1-AR) and its subtypes, α1A and α1B, activation on the proliferation of cultured vascular smooth muscle cells (VSMC) was studied by [3H]-thymidine (3H-TdR) incorporation and in situ hybridization. Norepinephrine (NE) promotes DNA synthesis of VSMC. The action was induced by activation of α1a-AR subtype and increase of c-fos gene expression. However, the DNA synthesis was in hibited by activation of α1B-AR subtype. There was a synergetic effect on VSMC DNA synthesis between NE and neuropeptide Y (NPY). But only additional effect was found between NE and Aug Ⅱ. More over, it was found that α1B-AR subtype showed significant constitutive inhibitory effect on VSMC DNA synthesis.