Local Anesthetics Suppress Nerve Growth Factor-Mediated Neurite Outgrowth by Inhibition of Tyrosine Kinase Activity of TrkA

Abstract

Local anesthetics (LAs) suppress sympathetic sprouting, which correlates with neuropathic pain. However, the precise mechanism of the suppression is unknown. Nerve growth factor (NGF) contributes to the sympathetic sprouting, and NGF signaling starts with NGF-stimulated autophosphorylation of TrkA, which is a high affinity receptor of NGF. We examined the effects of lidocaine, bupivacaine, and procaine on NGF signaling under suppression of NGF-stimulated neurite outgrowth in PC12 cells, which is a cellular model of sympathetic sprouting. To investigate the effect of these LAs on NGF-mediated neurite outgrowth of PC12 cells, cells were incubated with 40, 400, and 4000 microM of each LA. The effect of LAs on NGF-stimulated TrkA activity was examined to analyze autophosphorylation of TrkA using immunoprecipitation and immunoblotting. Cytotoxic effects of LAs on PC12 cells were also assessed by lactate dehydrogenase release and by propidium iodide staining. Lidocaine (400 microM), bupivacaine (40 and 400 microM), or procaine (4000 microM) suppressed either neurite outgrowth or autophosphorylation significantly without cytotoxicity. The inhibition of NGF-stimulated tyrosine kinase activity of TrkA might be involved in the mechanisms of suppression of neurite outgrowth induced by LAs.

Post Traumatic Stress Disorder (PTSD) as an Over Activation of Sympathetic Nervous System: An Alternative View

“…PTSD patients have known increase in norepinephrine (NE) concentrations as discussed in the back ground section above. The final part of this hypothesis is the evidence that the application of local anesthetic to a sympathetic ganglion leads to the reduction of NGF [32] The NGF decrease leads to dying of new nerve outgrowth or sprouts [33], thus reversing the cascade and reducing NE levels. Reduction of NE following SGB has been shown in a human model by [34].…”

Effect of Synthetic Cell-Penetrating Peptides on TrkA Activity in PC12 Cells

“…Amino acid sequence of the activation loop in TrkA reveals homology with that of the insulin receptor (8,9). On the other hand, there is no homology in amino acid sequences among the autophosphorylation sites of TrkA and epidermal growth factor (EGF) receptor (EGFR) (841 EEKEYHAE 848, 988 DADEYLI 994, 1101 RDPHYQD 1107, 1144 DNPDYQQDFF 1153, 1169 ENAEYLR 1175) (13).…”

“…Our previous studies indicated that there is a close resemblance of amino acid sequences between the activation loop of the insulin receptor (1154 TRDIYETDYYR 1164) and that of TrkA (666 SRDIYSTDYYR 676) (8,9). As the synthetic peptide DIYET, an analogue of the amino-acid sequence in the activation loop of insulin receptor, inhibited tyrosine kinase activity of the insulin receptor (8), we hypothesized that a synthetic peptide analogous to the aminoacid sequence in the activation loop of TrkA would be a new agent to antagonize TrkA function intracellularly and would suppress pain state more effectively.…”

Repeated Exposures to Hyperbaric Air Suppress Neurite Outgrowth in PC12 Cells

“…Recent advances in hyperbaric research have revealed that the direct effects of hyperbaric exposure on the intracellular properties of neural cells result in nitrogen narcosis, oxygen toxicity, carbon dioxide toxicity, and high-pressure nervous syndrome [4][5][6][7]. We therefore hypothesized that hyperbaric exposure would directly cause lesions of neural cells, depending on the degree of hyperbaric exposure.The PC12 cell line derived from rat pheochromocytoma shows neurite outgrowth stimulated by nerve growth factor (NGF) [8,9], and offers a suitable cellular model of neurodegeneration, neurodevelopment, and neural cell death [10][11][12]. NGF binding to the extracellular portion of TrkA, a high affinity receptor of NGF, leads to the autophosphorylation of five different tyrosine residues in the intracellular portion, located in the juxtamembrane domain (Y490), of the activation loop of the tyrosine kinase domain (Y670, Y674, Y675), and in the C-terminal (Y785) [13,14].…”

“…The PC12 cell line derived from rat pheochromocytoma shows neurite outgrowth stimulated by nerve growth factor (NGF) [8,9], and offers a suitable cellular model of neurodegeneration, neurodevelopment, and neural cell death [10][11][12]. NGF binding to the extracellular portion of TrkA, a high affinity receptor of NGF, leads to the autophosphorylation of five different tyrosine residues in the intracellular portion, located in the juxtamembrane domain (Y490), of the activation loop of the tyrosine kinase domain (Y670, Y674, Y675), and in the C-terminal (Y785) [13,14].…”