title: Pre-treatment with lidocaine suppresses ectopic discharges and attenuates neuropeptide Y and c-Fos expressions in the rat cuneate nucleus following median nerve transection.
abstract: Following peripheral nerve injury, lidocaine application has been demonstrated to suppress injury discharges. However, there is very little information about the effects of lidocaine pre-treatment. The aim of the present study was to examine the effects of pre-treatment with lidocaine on injury discharges of the nerve, and neuropeptide Y (NPY) and c-Fos expression in the cuneate nucleus (CN) after median nerve transection (MNT). Rats received either saline or 1%, 5%, or 10% lidocaine applied topically to the median nerve before nerve transection. Electrophysiological recording was used to examine the changes in injury discharges of the nerve at post-injection, transection, pre- and post-electrical stimulation stages in the different groups. Sequential immunohistochemistry was also used to identify the number of NPY-like immunoreactive (NPY-LI) fibers and c-Fos-LI cells in the corresponding CN. An increasing frequency of injury discharges was observed at all stages in the pre-saline group, which were suppressed by lidocaine pre-treatment in a dose-dependent manner. Lidocaine pre-treatment also attenuated the number of injury-induced NPY-LI fibers and c-Fos-LI neurons within the CN in a dose-dependent manner. Furthermore, expression of c-Fos-LI neurons in the CN was significantly reduced by an NPY receptor antagonist, indicating that NPY modulated c-Fos expression following MNT. These data suggest that preventing injury discharges with lidocaine pre-treatment can effectively attenuate central sensitization following MNT.
authors: Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors: Chi-Te
authors: CT
authors: Lin
authors: Hsin-Ying
authors: HY
authors: Wang
authors: Yi-Ju
authors: YJ
authors: Tsai
authors: Chun-Ta
authors: CT
authors: Huang
authors: Seu-Hwa
authors: SH
authors: Chen
authors: June-Horng
authors: JH
authors: Lue
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000344:Afferent Pathways / Q000293:injuries / Q000378:metabolism* / Q000601:surgery; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002452:Cell Count; D004305:Dose-Response Relationship, Drug; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology; D007150:Immunohistochemistry; D008012:Lidocaine / Q000494:pharmacology*; D008297:Male; D008475:Median Nerve / Q000293:injuries / Q000378:metabolism* / Q000601:surgery; D008526:Medulla Oblongata / Q000033:anatomy & histology / Q000378:metabolism*; D009431:Neural Conduction / Q000187:drug effects / Q000502:physiology; D009478:Neuropeptide Y / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors / Q000378:metabolism; D018013:Receptors, Neuropeptide / Q000037:antagonists & inhibitors / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
chemical_list: D000779:Anesthetics, Local; D009478:Neuropeptide Y; C066211:Npy1r protein, rat; D016760:Proto-Oncogene Proteins c-fos; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide; D008012:Lidocaine