环磷酸腺苷对心肌细胞血管紧张素Ⅱ 1型受体基因转录调节的影响

The Effect of cAMP on the Transcription and Regulation of Angiotensin Ⅱ Type 1 Receptor Gene in Cardiomyocytes of Neonatal Rats

目的 从信号转导的角度探讨环磷酸腺苷（ｃＡＭＰ）在心肌细胞血管紧张素Ⅱ１ 型（ＡＴ１）受体基因转录调节中的作用。方法 取１～３ ｄ 的ＳＤ乳鼠心脏，用胰蛋白酶消化、差速贴壁分离法获得心肌细胞，用ＤＭＥＭ 培养基进行培养并以相应药物给予刺激；采用逆转录多聚酶链反应（ＲＴＰＣＲ）测定ＡＴ１ 受体ｍ ＲＮＡ 丰度。结果 ３０μｍ ｏｌ／Ｌｆｏｒｓｋｏｌｉｎ （腺苷酸环化酶激活剂）与３０ μｍ ｏｌ／ＬＩＢＭＸ（磷酸二脂酶抑制剂）合用后ＡＴ１ 受体ｍ ＲＮＡ 的表达先呈下降，至６ ｈ 时达最低点，其表达量仅为对照组的（６４４±２０３）％ （Ｐ＜ ００１），随后逐渐回升，４８ ｈ 时达到对照组的（２０９６±２４０）％ （Ｐ＜ ００１）。结论 ｃＡＭＰ参与培养的乳鼠心肌细胞的ＡＴ１

r Objective To clarify the effect of cAMP on the transcription of angiotensin Ⅱ type 1(AT 1) receptor mRNA in cardiomyocytes.Methods Cardiomyocytes from SD neonatal rats were cultured in DMEM containing 10% fetal bovine serum (FBS) with 0 1 mmol/L 5 bromodeoxyuridine (Brdu) .At day 5～7, primary cultured cells were used. FBS and Brdu were deprived 24 h before the stimulation. The levels of AT 1 mRNA in primary cultured cardiomyocytes were examined by RT PCR. Results Stimulation of forskolin (30 μmol/L) plus 3 isobutyl 1 methyl xanthine (IBMX,30 μmol/L) which induced the accumulation of cellular cAMP decreased the expression of AT 1 receptor mRNA to (64 4±20 3)% of control at 6 h treatment; while it increased the expression of AT 1 receptor mRNA to (209 6±24 0)% of control at 48 h treatment.Conclusions cAMP regulated the transcription of AT 1 receptor gene.