title: Role of spinal voltage-dependent calcium channel alpha 2 delta-1 subunit in the expression of a neuropathic pain-like state in mice.
abstract: The present study was undertaken to investigate the role of spinal voltage-dependent calcium channel alpha(2)delta-1 subunit in the expression of a neuropathic pain-like state induced by partial sciatic nerve ligation in mice. In cultured spinal neurons, gabapentin (GBP), which displays the inhibitory effect of alpha(2)delta-1 subunit, suppressed the extracellular Ca(2+) influx induced by KCl, whereas it failed to inhibit the intracellular Ca(2+) release induced by inositol-1,4,5-triphosphate. Seven days after sciatic nerve ligation, the protein level of alpha(2)delta-1 subunit in the ipsilateral spinal cord was clearly increased compared to that observed in sham-operated mice. In addition, the mRNA level of alpha(2)delta-1 subunit was significantly increased in the dorsal root ganglion, but not in the spinal cord, of nerve-ligated mice. Under these conditions, a marked decrease in the latency of paw-withdrawal against a thermal stimulation and tactile stimulation, induced by sciatic nerve ligation was abolished by repeated intrathecal (i.t.) treatment with GBP. Additionally, the persistent reduction in the nociceptive threshold by i.t. treatment with GBP at the early stage of the neuropathic pain-like state was maintained for 7 days even after GBP withdrawal. It is of interest to note that a single i.t. post-injection of GBP showed a marked and transient inhibitory effect on the developed neuropathic pain-like state, whereas repeated i.t. post-treatment with GBP produced a persistent inhibitory effect during the treatment. In conclusion, we propose here that the neuropathic pain-like state with sciatic nerve ligation is associated with the increased level of the alpha(2)delta-1 subunit of Ca(2+) channels at the sensory nerve terminal in the spinal dorsal horn of mice. Furthermore, the present data provide evidence that the neuropathic pain may be effectively controlled by repeated treatment with GBP at the early stage.
authors: Department of Toxicology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo, 142-8501, Japan. narita@hoshi.ac.jp
authors: Minoru
authors: M
authors: Narita
authors: Mayumi
authors: M
authors: Nakajima
authors: Kan
authors: K
authors: Miyoshi
authors: Michiko
authors: M
authors: Narita
authors: Yasuyuki
authors: Y
authors: Nagumo
authors: Mayumi
authors: M
authors: Miyatake
authors: Yoshinori
authors: Y
authors: Yajima
authors: Kiyomi
authors: K
authors: Yanagida
authors: Mitsuaki
authors: M
authors: Yamazaki
authors: Tsutomu
authors: T
authors: Suzuki
mesh_terms: D000588:Amines / Q000008:administration & dosage*; D000700:Analgesics / Q000008:administration & dosage*; D000818:Animals; D015220:Calcium Channels / Q000096:biosynthesis / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage*; D004195:Disease Models, Animal; D000077206:Gabapentin; D015870:Gene Expression / Q000187:drug effects; D007278:Injections, Spinal; D008297:Male; D051379:Mice; D010147:Pain Measurement; D017288:Pain Threshold; D021122:Protein Subunits; D012333:RNA, Messenger / Q000187:drug effects; D012585:Sciatica / Q000188:drug therapy* / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage*
chemical_list: D000588:Amines; D000700:Analgesics; D015220:Calcium Channels; D003509:Cyclohexanecarboxylic Acids; D021122:Protein Subunits; D012333:RNA, Messenger; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin