Pre-treatment with lidocaine suppresses ectopic discharges and attenuates neuropeptide Y and c-Fos expressions in the rat cuneate nucleus following median nerve transection.
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.
Lin
Chi-Te
CT
Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
Wang
Hsin-Ying
HY
Tsai
Yi-Ju
YJ
Huang
Chun-Ta
CT
Chen
Seu-Hwa
SH
Lue
June-Horng
JH
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
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