Chabrier P E, Roubert P, Braquet P
Institut Henri-Beaufour, Les Ulis France.
Arch Mal Coeur Vaiss. 1989 Jul;82(7):1249-51.
Two subtypes of atrial natriuretic factor (ANF) receptors are present in vascular smooth muscle cells: B(biologically active) receptors coupled to a guanylate cyclase and C (clearance) receptors (95 per cent of the total number of ANF binding sites) non coupled to any identified second messenger system. We compared the homologous receptor regulation induced by ANF to the heterologous one elicited by angiotensin II (Ag II). Binding of (3-[125I]iodotyrosyl) rat ANF and cGMP production stimulated by ANF were measured after 18 hours preincubation of rat cultured vascular smooth muscle cells (10(6) cells/dish) at 37 degrees C with ANF or Ag II. The hormones (10 nM) decreased to the same extent the total apparent number of ANF binding sites (control: 208 +/- 25 fmol/10(6); ANF : 82 +/- 20 fmol/10(6) cells; Ag II : 90 +/- 9 fmol/10(6) cells) The diminution of the number of ANF binding sites induced by ANF exposure was reversed by 85 per cent following 10 minutes treatment of the cells with 10 mM AcOH. Moreover, treatment with ANF (10 nM) led to a diminution of cGMP stimulation induced by ANF, this effect being still present after washing the cells with 10 mM AcOH. In contrast, diminution of ANF building sites consecutive to Ag II exposure was not affected by AcOH treatment and a potentiation of cGMP production elicited by ANF was observed. These results suggest that, in rat vascular smooth muscle cells, B receptors are sensitive to homologous down regulation and C receptors are sensitive to heterologous regulation by Ag II.
血管平滑肌细胞中存在两种心房利钠因子（ANF）受体亚型：与鸟苷酸环化酶偶联的B（生物活性）受体和不与任何已确定的第二信使系统偶联的C（清除）受体（占ANF结合位点总数的95%）。我们比较了ANF诱导的同源受体调节与血管紧张素II（Ag II）引发的异源受体调节。在37℃下将大鼠培养的血管平滑肌细胞（10⁶个细胞/培养皿）与ANF或Ag II预孵育18小时后，测量（3-[¹²⁵I]碘酪氨酰）大鼠ANF的结合以及ANF刺激产生的环磷酸鸟苷（cGMP）。这些激素（10 nM）使ANF结合位点的总表观数量降低到相同程度（对照：208±25 fmol/10⁶；ANF：82±20 fmol/10⁶个细胞；Ag II：90±9 fmol/10⁶个细胞）。用10 mM乙酸处理细胞10分钟后，ANF暴露诱导的ANF结合位点数量减少有85%得到逆转。此外，用ANF（10 nM）处理导致ANF刺激产生的cGMP减少，在用10 mM乙酸洗涤细胞后这种效应仍然存在。相反，Ag II暴露后ANF结合位点的减少不受乙酸处理的影响，并且观察到ANF引发的cGMP产生增强。这些结果表明，在大鼠血管平滑肌细胞中，B受体对同源下调敏感，C受体对Ag II的异源调节敏感。
