Göõz Monika, Tóth Miklós, Vakkuri Olli, Göõz Pal, Smolka Adam J, de Châtel Rudolf, Szalay Katalin Sz
Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, 1083 Budapest, Hungary.
Life Sci. 2004 Mar 12;74(17):2111-28. doi: 10.1016/j.lfs.2003.07.058.
This study tested the hypothesis that rat adrenocortical secretion of endogenous ouabain-like factor (OLF) is regulated by nicotinic mechanisms. OLF secreted by dispersed cell suspensions of zona glomerulosa (ZG) and fasciculata/reticularis (ZFR) cells was found to co-elute with authentic ouabain by reverse phase HPLC; OLF concentrations in cell supernatants were measured by radioimmunoassay. Nicotine (10(-6) - 10(-3) M) stimulated significant OLF secretion in rat adrenocortical cells. Acetylcholine (10(-7) - 10(-4) M) and eserine (10(-7) - 10(-3) M) stimulated OLF secretion in ZG cells at lower concentrations and stimulated at higher concentrations. Acetylcholine had no effect on ZFR secretion of OLF, but eserine stimulated OLF secretion. ACTH (10(-8) M) strongly potentiated the OLF stimulatory effect of nicotine in ZG cells; however significant interactions between nicotine and ACTH or angiotensin II on OLF secretion in ZFR cells were not apparent. The ganglionic blockers hexamethonium and mecamylamine further potentiated the effect of nicotine, implicating nicotinic acetylcholine receptors (nAChRs) in regulation of OLF secretion. The alpha7-receptor antagonist methyllycaconitine (MLA) dose-dependently inhibited the effect of nicotine in the ZG cells, and in ZFR cells MLA potentiated nicotine-induced OLF secretion. These data suggest that nicotinic regulation may underlie OLF secretion by rat adrenocortical cells, and strongly suggest presence of functional nicotinic acetylcholine receptors on these cells.
本研究检验了大鼠肾上腺皮质分泌内源性哇巴因样因子（OLF）受烟碱机制调节这一假说。通过反相高效液相色谱法发现，肾小球带（ZG）和束状带/网状带（ZFR）细胞的分散细胞悬液分泌的OLF与纯品哇巴因共洗脱；采用放射免疫分析法测定细胞上清液中的OLF浓度。尼古丁（10⁻⁶ - 10⁻³ M）刺激大鼠肾上腺皮质细胞显著分泌OLF。乙酰胆碱（10⁻⁷ - 10⁻⁴ M）和毒扁豆碱（10⁻⁷ - 10⁻³ M）在较低浓度时刺激ZG细胞分泌OLF，在较高浓度时也有刺激作用。乙酰胆碱对ZFR细胞分泌OLF无影响，但毒扁豆碱刺激其分泌OLF。促肾上腺皮质激素（ACTH，10⁻⁸ M）强烈增强尼古丁对ZG细胞分泌OLF的刺激作用；然而，尼古丁与ACTH或血管紧张素II对ZFR细胞分泌OLF的显著相互作用并不明显。神经节阻滞剂六甲铵和美加明进一步增强了尼古丁的作用，提示烟碱型乙酰胆碱受体（nAChRs）参与OLF分泌的调节。α7受体拮抗剂甲基lycaconitine（MLA）剂量依赖性地抑制尼古丁对ZG细胞的作用，而在ZFR细胞中，MLA增强尼古丁诱导的OLF分泌。这些数据表明，烟碱调节可能是大鼠肾上腺皮质细胞分泌OLF的基础，并强烈提示这些细胞上存在功能性烟碱型乙酰胆碱受体。
