腺苷诱导原代培养大鼠系膜细胞的膜电压超极化。

Adenosine-induced hyperpolarization of the membrane voltage in rat mesangial cells in primary culture.

作者信息

Pavenstädt H, Ruh J, Greger R, Schollmeyer P

机构信息

Department of Medicine, Albert-Ludwigs University, Freiburg, Germany.

出版信息

Br J Pharmacol. 1994 Sep;113(1):7-12. doi: 10.1111/j.1476-5381.1994.tb16166.x.

DOI:10.1111/j.1476-5381.1994.tb16166.x

PMID:7529114

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1510083/

Abstract

The effect of adenosine on membrane voltage and ion currents was studied in rat mesangial cells in primary culture. Membrane voltage was measured with the patch clamp technique in the slow- or fast whole cell configuration. The resting membrane voltage of mesangial cells was -48 +/- 0.5 mV. Adenosine (10(-8)-10(-3) M) induced a sustained and concentration-dependent hyperpolarization of membrane voltage (ED50 approximately 6 x 10(-7) M). Adenosine (10(-5) M) hyperpolarized the membrane voltage by 14 +/- 0.5 mV. During the hyperpolarization ion currents were monitored simultaneously. An increase of the outward current by 51 +/- 11% was observed. 2. An increase of the extracellular K+ concentration (from 3.6 to 18.6 M) caused a depolarization of membrane voltage to -34 +/- 2 mV. In the presence of increased K+ the hyperpolarization of membrane voltage induced by adenosine was significantly attenuated by 61 +/- 5%. The K(+)-channel blocker, Ba2+ (5 x 10(-3) M) depolarized membrane voltage to -24 +/- 2 mV. In the presence of Ba2+ the adenosine-induced hyperpolarization was significantly inhibited by 72 +/- 8%. 3. Preincubation of the adenosine antagonist, 8-phenyltheophylline (10(-4) M) significantly inhibited the adenosine (10(-5) M) mediated membrane voltage response by 67 +/- 8%. The adenosine agonists 5-N-ethylcarboxamidoadenosine (NECA), R-(-)N6-(2-phenylisopropyl)adenosine (R-(-)-PIA), S-(+)-N6-(2-phenylisopropyl)adenosine (S-(+)-PIA), N6-[2-(3,5-dimethoxyphenyl)-2-(2-methylphenyl)-ethyl]adenosine (DPMA), and 2-chloroadenosine (2-CA) also hyperpolarized membrane voltage of mesangial cells. The rank order of potency of the agonists at 10-5 M was NECA> adenosine = > R-(-)-PIA = DPMA = 2-CA > S-( + )-PIA.4. Stimulation of cyclic AMP by forskolin induced a concentration-dependent hyperpolarization of membrane voltage (ED50 2 x 10-7 M). Application of forskolin (10-5 M) in the presence of adenosine(10-4 M) had no additive hyperpolarizing effect on the membrane voltage.5. Activation of protein kinase C by phorbol 12,13 dibutyrate (PDBu) induced a sustained depolarization of membrane voltage (ED50 5 x 10-9 M). In the presence of PDBu, adenosine (10-5 M) still hyperpolarized membrane voltage of mesangial cells.6. The data indicate that adenosine activates K+-conductance via an A2 receptor in mesangial cells; the activation of the K+-conductance, which is probably mediated by cyclic AMP led to a hyperpolarization of membrane voltage.

摘要

在原代培养的大鼠系膜细胞中研究了腺苷对膜电压和离子电流的影响。采用膜片钳技术在慢或快全细胞模式下测量膜电压。系膜细胞的静息膜电压为-48±0.5 mV。腺苷（10⁻⁸ - 10⁻³ M）引起膜电压持续且浓度依赖性的超极化（半数有效浓度约为6×10⁻⁷ M）。腺苷（10⁻⁵ M）使膜电压超极化14±0.5 mV。在超极化过程中同时监测离子电流。观察到外向电流增加了51±11%。2. 细胞外钾离子浓度升高（从3.6 mM增加到18.6 mM）导致膜电压去极化至-34±2 mV。在钾离子浓度增加的情况下，腺苷诱导的膜电压超极化显著减弱了61±5%。钾通道阻滞剂Ba²⁺（5×10⁻³ M）使膜电压去极化至-24±2 mV。在Ba²⁺存在的情况下，腺苷诱导的超极化被显著抑制了72±8%。3. 腺苷拮抗剂8-苯基茶碱（10⁻⁴ M）预孵育显著抑制了腺苷（10⁻⁵ M）介导的膜电压反应，抑制率为67±8%。腺苷激动剂5-N-乙基羧基酰胺腺苷（NECA）、R-(-)-N⁶-(2-苯异丙基)腺苷（R-(-)-PIA）、S-(+)-N⁶-(2-苯异丙基)腺苷（S-(+)-PIA）、N⁶-[2-(3,5-二甲氧基苯基)-2-(2-甲基苯基)-乙基]腺苷（DPMA）和2-氯腺苷（2-CA）也使系膜细胞膜电压超极化。在10⁻⁵ M时激动剂的效力顺序为NECA>腺苷 => R-(-)-PIA = DPMA = 2-CA > S-( + )-PIA。4. 福斯可林刺激环磷酸腺苷（cAMP）诱导膜电压浓度依赖性超极化（半数有效浓度约为2×10⁻⁷ M）。在腺苷（10⁻⁴ M）存在的情况下应用福斯可林（10⁻⁵ M）对膜电压没有叠加的超极化作用。5. 佛波醇12,13-二丁酸酯（PDBu）激活蛋白激酶C诱导膜电压持续去极化（半数有效浓度约为5×10⁻⁹ M）。在PDBu存在的情况下，腺苷（10⁻⁵ M）仍使系膜细胞膜电压超极化。6. 数据表明，腺苷通过系膜细胞中的A2受体激活钾离子电导；钾离子电导的激活可能由环磷酸腺苷介导，导致膜电压超极化。