Mechanisms of suppression of insulin signaling by Na channel blockers

1)局麻利多卡因和多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的自磷酸化在20%以下或以上。2)利多卡因和各种寡肽对预磷酸化IR的去磷酸化作用40 mM的利多卡因和4 mM的KIYEK和DIYET分别使预磷酸化IR的磷酸化水平降低了35%和30%。而KIFMK则无去磷酸化作用。3)红外激活环肽（AL）与利多卡因或寡肽之间的相互作用。多卡因、KIYEK和DIYET对激活的红外具有去磷酸化作用，在280 nm激发和303 nm发射下，AL的荧光强度降低。而KIFMK没有去磷酸化作用，反而增强了强度。LPFFD对强度无影响。4)利用表面等离子体共振（SPR）实验研究利多卡因和寡肽对IR的去磷酸化作用通过不同的固定配体和流动缓冲液对分析物进行各种SPR实验，得出SPR方法不足以分析IR的磷酸化作用。研究了EGFR自磷酸化位点的氨基酸序列与EGFR自磷酸化的关系。Y1148和Y1173周围氨基酸序列后面的寡肽被发现能有效抑制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.