Implications of Ca(2+)-activated Cl(-) channels in the delta-opioid receptor-mediated antinociception in the mouse spinal cord.
The present study was designed to investigate the role of Ca(2+)-activated Cl(-) channels in the spinal opioid receptor-mediated antinociception using the mouse tail-flick assay. The antinociception induced by intrathecal (i.t.) administration of a selective delta-opioid receptor agonist [D-Ala(2)]deltorphin II (10 microgram, i.t.) was significantly attenuated by i.t.-pretreatment with selective Ca(2+)-activated Cl(-) channel blockers, IAA-94, flufenamic acid and niflumic acid. By contrast, IAA-94 had no effect on the antinociception induced by i.t.-treated with either the selective mu-opioid receptor agonist [D-Ala(2),N-MePhe(4), Gly-ol(5)]enkephalin or the kappa-opioid receptor agonist U-50,488H. The present results provide evidence for the first time that the Ca(2+)-activated Cl(-) channel is, at least in part, implicated in the delta-, but not the mu- and kappa-opioid receptor-mediated antinociception in the mouse spinal cord.
Yamazaki
M
M
Department of Anesthesiology, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama, 930-0194, Toyama, Japan. myama@ms.toyama-mpu.ac.jp
Mizoguchi
H
H
Ohsawa
M
M
Tseng
L F
LF
Suzuki
T
T
Narita
M
M
D000698:Analgesia / Q000379:methods*; D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects* / Q000502:physiology; D018118:Chloride Channels / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009619:Nociceptors / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D010146:Pain / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology; D017465:Receptors, Opioid, delta / Q000819:agonists* / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D000701:Analgesics, Opioid; D018118:Chloride Channels; D009842:Oligopeptides; D017465:Receptors, Opioid, delta; C082680:deltorphin, Ala(2)-Cys(4)-