Mechanisms of suppression of insulin signaling by Na channel blockers

1)局部麻醉剂利多卡因和各种寡肽对胰岛素受体（IR）自磷酸化的抑制40 mM利多卡因和4 mM寡肽KIFMK和KIYEK抑制IR自磷酸化低于20%或更高。DIYET和KIQMK抑制自身磷酸化的效果不如KIFMK和KIYEK。2）利多卡因和各种寡肽对预磷酸化IR的去磷酸化40mM利多卡因和4mM KIYEK和DIYET分别将预磷酸化IR的磷酸化降低至35%和30%。3）IR激活环肽（AL）与利多卡因或寡肽的相互作用对激活的IR具有去磷酸化作用的利多卡因、KIYEK和DIYET均能降低AL在280 nm激发和303 nm发射的荧光强度。与此相反，KIFMK，它没有表现出去磷酸化作用，增加了强度。LPFFD对强度没有影响。4）通过表面等离子体共振（SPR）实验研究利多卡因和寡肽对IR的去磷酸化作用在通过改变待固定的配体和待流动的分析物与运行缓冲液进行的各种SPR实验之后，结论是SPR方法不足以分析IR的磷酸化。5）抑制表皮生长因子受体（EGFR）的自磷酸化研究了氨基酸序列与EGFR自身磷酸化位点一致的寡肽对EGFR自身磷酸化的抑制作用。发现在Y1148和Y1173附近的氨基酸序列之后的寡肽有效地抑制EGFR的自磷酸化。

1)Suppression of autophosphorylation of insulin receptor(IR) by local anesthetic lidocaine and various oligopeptidesThe 40 mM of lidocaine and the 4 mM of oligopeptides, KIFMK and KIYEK, suppressed autophosphorylation of IR below 20% or more. DIYET and KIQMK, suppressed autophosphorylation less effectively than did KIFMK and KIYEK.2)Dephosphorylation of pre-phosphorylated IR by lidocaine and various oligopeptidesThe 40 mM of lidocaine and 4 mM of KIYEK and DIYET decreased phosphorylation of pre-phosphorylated IR to 35 and 30%, respectively. In contrast, KIFMK showed no dephosphorylation effect.3)Interactions between activation loop peptide(AL) of IR and lidocaine or oligopeptides by fluorescence spectraLidocaine, KIYEK, and DIYET, which had dephosphorylation effects on activated IR, reduced fluorescence intensities of AL due to 280 nm excitation and 303 nm emission. In contrast, KIFMK, which showed no dephosphorylation effect, increased the intensities. LPFFD had no effect on the intensities.4)Dephosphorylation effects for IR by lidocaine and oligopeptides as studied by surface plasmon resonance(SPR) experimentsAfter various SPR experiments performed by varying ligands to be immobilized and analytes to be flowed with running buffer, it was concluded that the SPR method is inadequate for analyzing phosphorylation of IR.5)Suppression of autophosphorylation of epidermal growth factor receptor(EGFR) by oligopeptidesSuppression effects of oligopeptides, the amino acid sequences of which followed those of autophosphorylation sites of EGFR, on autophosphorylation of EGFR were studied. The oligopeptides which followed the amino acid sequences around Y1148 and Y1173 were found to effectively suppress autophoshorylation of EGFR.