title: Synaptic modulation of excitatory synaptic transmission by nicotinic acetylcholine receptors in spinal ventral horn neurons.
abstract: Nicotinic acetylcholine receptors (nAChRs) are distributed widely in the central nervous system and play important roles in higher brain functions, including learning, memory, and recognition. However, functions of the cholinergic system in spinal motoneurons remain poorly understood. In this study, we investigated the actions of presynaptic and postsynaptic nAChRs in spinal ventral horn neurons by performing whole-cell patch-clamp recordings on lumbar slices from male rats. The application of nicotine or acetylcholine generated slow inward currents and increased the frequency and amplitude of spontaneous excitatory postsynaptic currents (sEPSCs). Slow inward currents by acetylcholine or nicotine were not inhibited by tetrodotoxin (TTX) or glutamate receptor antagonists. In the presence of TTX, the frequency and amplitude of miniature excitatory postsynaptic currents (mEPSCs) were also increased by acetylcholine or nicotine. A selective α4β2 nicotinic receptor antagonist, dihydro-β-erythroidine hydrobromide (DhβE), significantly decreased nicotine-induced inward currents without affecting the enhancement of sEPSCs and mEPSCs. In addition, a selective α7 nicotinic receptor antagonist, methyllycaconitine, did not affect either nicotine-induced inward currents or the enhancement of sEPSCs and mEPSCs. These results suggest that α4β2 AChRs are localized at postsynaptic sites in the spinal ventral horn, non-α4β2 and non-α7 nAChRs are located presynaptically, and nAChRs enhance excitatory synaptic transmission in the spinal ventral horn.
authors.affiliation: Department of Orthopedic Surgery, Wakayama Medical University, Wakayama 641-8510, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Mine
authors.affiliation: Pain Research Center, Kansai University of Health Sciences, Kumatori, Osaka 590-0482, Japan. Electronic address: wtaniguchi@kansai.ac.jp.
authors.forename: W
authors.initials: W
authors.lastname: Taniguchi
authors.affiliation: Pain Research Center, Kansai University of Health Sciences, Kumatori, Osaka 590-0482, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Nishio
authors.affiliation: Department of Orthopedic Surgery, Wakayama Medical University, Wakayama 641-8510, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Izumi
authors.affiliation: Department of Orthopedic Surgery, Wakayama Medical University, Wakayama 641-8510, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Miyazaki
authors.affiliation: Department of Orthopedic Surgery, Wakayama Medical University, Wakayama 641-8510, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yamada
authors.affiliation: Pain Research Center, Kansai University of Health Sciences, Kumatori, Osaka 590-0482, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nakatsuka
authors.affiliation: Department of Orthopedic Surgery, Wakayama Medical University, Wakayama 641-8510, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D000870:Anterior Horn Cells / Q000187:drug effects / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D008161:Lumbosacral Region; D008297:Male; D055369:Miniature Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D017207:Rats, Sprague-Dawley; D011978:Receptors, Nicotinic / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D046509:Tissue Culture Techniques
chemical_list: D011978:Receptors, Nicotinic
keywords: motoneurons; nicotinic acetylcholine receptors; patch-clamp; spinal cord; ventral horn