Jiang Z L, Ye J-H
Department of Anesthesiology, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ 07103-2714, USA.
Neuropharmacology. 2003 Mar;44(4):493-502. doi: 10.1016/s0028-3908(02)00409-4.
Previously, we demonstrated that ethanol potentiates glycine current (I(Gly)) in 35% of neurons freshly isolated from the ventral tegmental area (VTA) of rats (J. Pharmacol. Exp. Ther. 296 (2001) 77). In the present study, we examined the role of protein kinase C (PKC) in this action of ethanol on VTA neurons from young rats. Extracellular ethanol and intracellular ATP-gamma-S when applied separately potentiated I(Gly). However, ethanol potentiation of I(Gly) was significantly reduced in neurons dialyzed with 2 mM ATP-gamma-S. Phorbol-12-myristate-13-acetate (PMA, 10 nM), a PKC activator also increased I(Gly) and reduced ethanol potentiation of I(Gly). In addition, GF109203X (0.2 microM), a PKC inhibitor antagonized the potentiation effects produced either by PMA or by ethanol. Thus, ethanol potentiation of I(Gly) may be associated with PKC activation. While intracellular application of 1,2-bis(aminophenoxy)-ethane-N,N,N,N'-tetraacetic acid, a Ca(2+) chelator or Gö6976, an inhibitor of Ca(2+)-dependent PKC had no appreciable effect on ethanol potentiation of I(Gly), translocation inhibitor peptide (PKC(epsilon)-TIP) (500 nM) significantly reduced ethanol potentiation, an action the translocation inhibitor peptide negative control (PKC(epsilon)-TIP-NC) (500 nM) did not have. These results suggest that the activation of PKC(epsilon) isoenzyme contributes to ethanol-induced potentiation of GlyR function.
此前，我们证明乙醇可增强从大鼠腹侧被盖区（VTA）新鲜分离的35%神经元中的甘氨酸电流（I(Gly)）（《药理学与实验治疗学杂志》296 (2001) 77）。在本研究中，我们研究了蛋白激酶C（PKC）在乙醇对幼鼠VTA神经元的这一作用中的作用。单独应用细胞外乙醇和细胞内ATP-γ-S可增强I(Gly)。然而，在用2 mM ATP-γ-S透析的神经元中，乙醇对I(Gly)的增强作用显著降低。佛波醇-12-肉豆蔻酸酯-13-乙酸酯（PMA，10 nM），一种PKC激活剂也增加了I(Gly)并降低了乙醇对I(Gly)的增强作用。此外，GF109203X（0.2 μM），一种PKC抑制剂，拮抗了PMA或乙醇产生的增强作用。因此，乙醇对I(Gly)的增强作用可能与PKC激活有关。虽然细胞内应用1,2-双（氨基苯氧基）乙烷-N,N,N,N'-四乙酸，一种Ca(2+)螯合剂或Gö6976，一种Ca(2+)依赖性PKC的抑制剂对乙醇对I(Gly)的增强作用没有明显影响，但转位抑制剂肽（PKC(ε)-TIP）（500 nM）显著降低了乙醇的增强作用，而转位抑制剂肽阴性对照（PKC(ε)-TIP-NC）（500 nM）则没有此作用。这些结果表明PKC(ε)同工酶的激活有助于乙醇诱导的甘氨酸受体（GlyR）功能增强。
