N- and L-type calcium channels blocker cilnidipine ameliorates neuropathic pain.
Cilnidipine is a dihydropyridine derivative that inhibits N-type and L-type voltage-gated Ca2+channels (VDCCs). We recently reported that a selective N-type VDCC blocker attenuated the spinal long-term potentiation (LTP) of C-fiber-evoked field potentials recorded in the spinal dorsal horn of rats, which served as a model for examining synaptic function during central pain sensitization. In this study, we investigated the effects of cilnidipine on the changes related to neuropathic pain induced by nerve injury. Mechanical allodynia and hyperalgesia were evaluated by von Frey test and pin prick test, respectively. Spinal LTP of C-fiber-evoked field potentials were evaluated by in vivo electrophysiology. Intrathecally administrated cilnidipine attenuated mechanical allodynia and hyperalgesia in the spared nerve injury mouse model. Using in vivo electrophysiology in rats, cilnidipine (10µm) administered spinally inhibited the induction and maintenance of high-frequency stimulation-induced LTP of C-fiber-evoked field potentials, while basal C-fiber-evoked field potentials in naïve rats were unaffected. The basal C-fiber-evoked field potentials in nerve-injured rats were strongly inhibited by cilnidipine. Treatment with a specific N-type VDCC blocker, ω-conotoxin GVIA, which reportedly attenuates C-fiber-evoked field potentials both before and after the induction of LTP, attenuated mechanical allodynia and hyperalgesia in nerve-injured mice. By contrast, an L-type VDCC blocker, nicardipine attenuated only mechanical hyperalgesia, but not mechanical allodynia in nerve-injured mice, and also attenuated the established LTP of C-fiber-evoked field potentials in rats. These results suggested that N-type and L-type VDCC blockers may effectively alleviate the hyperalgesia and allodynia associated with neuropathic pain without affecting normal pain perception.
Department of Neuropharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan; Laboratory of CNS Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan.
Shohei
S
Yamamoto
Laboratory of CNS Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan.
Yuma
Y
Suzuki
Laboratory of CNS Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan; Laboratory of Clinical Pharmacy and Pharmacology, Faculty of Pharmacy, Musashino University, 1-1-20 Shinmachi, Nishitokyo-shi, Tokyo 202-8585, Japan.
Hideki
H
Ono
Department of Neuropharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
Kazuhiko
K
Kume
Department of Neuropharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan; Laboratory of CNS Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan. Electronic address: ohsawa@phar.nagoya-cu.ac.jp.
Masahiro
M
Ohsawa
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology* / Q000627:therapeutic use; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D020864:Calcium Channels, N-Type / Q000378:metabolism*; D020916:Conotoxins / Q000633:toxicity; D004095:Dihydropyridines / Q000494:pharmacology* / Q000627:therapeutic use; D005071:Evoked Potentials / Q000187:drug effects; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D051379:Mice; D036421:Nerve Fibers, Unmyelinated / Q000187:drug effects / Q000473:pathology; D009437:Neuralgia / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D009529:Nicardipine / Q000494:pharmacology; D051381:Rats; D066148:Spinal Cord Dorsal Horn / Q000473:pathology
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D020864:Calcium Channels, N-Type; D020916:Conotoxins; D004095:Dihydropyridines; C055407:conotoxin GV; C065927:cilnidipine; D009529:Nicardipine
Cilnidipine; Cilnidipine (PubChem CID: 5282138); Long term potentiation; Neuropathic pain; Spinal cord; Voltage-gated Ca(2+) channels blocker; nicardipine HCl (PubChem CID: 41114); ω-conotoxin GVIA (PubChem CID: 16132374)