title: Involvement of GABA A receptor-associated chloride channels in the peripheral antinociceptive effect induced by GABA A receptor agonist muscimol.
abstract: The effect of chloride and potassium channel blockers on the antinociception induced by GABA(A) receptor agonist muscimol was investigated using the paw pressure test. Muscimol (1, 2, 4, 8 ng/paw) elicited a peripheral antinociceptive effect that was antagonized by bicuculline (10, 20, 40, 80 ng/paw), suggesting a specific effect. The muscimol effect was reverted by the chloride channel coupled GABA(A) receptor blocker, picrotoxin (0.4, 0.6, 0.8, 2 microg/paw). Potassium channel blockers did not modify the peripheral antinociception induced by muscimol. This study provides evidence that the peripheral antinociceptive effect of muscimol results from the activation of GABA(A) receptor-associated chloride channels.
authors: Department of Pharmacology, Institute of Biological Sciences, Federal University of Minas Gerais, Av. Antônio Carlos 6627, 31270-100 Belo Horizonte, MG, Brazil.
authors: Glaucia
authors: G
authors: Reis
authors: Daniela
authors: D
authors: Pacheco
authors: Janetti
authors: J
authors: Francischi
authors: Maria
authors: M
authors: Castro
authors: Andréa
authors: A
authors: Perez
authors: Igor
authors: I
authors: Duarte
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001640:Bicuculline / Q000008:administration & dosage / Q000494:pharmacology; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000378:metabolism; D015232:Dinoprostone; D004305:Dose-Response Relationship, Drug; D018755:GABA Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D018756:GABA Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D007279:Injections, Subcutaneous; D008297:Male; D009118:Muscimol / Q000008:administration & dosage / Q000494:pharmacology*; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy*; D010147:Pain Measurement; D010852:Picrotoxin / Q000008:administration & dosage / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism; D011312:Pressure; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects* / Q000378:metabolism
chemical_list: D001640:Bicuculline; D018118:Chloride Channels; D015232:Dinoprostone; D018755:GABA Agonists; D018756:GABA Antagonists; D009118:Muscimol; D010852:Picrotoxin; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D011963:Receptors, GABA-A