A study on the involvement of GABAB receptor ligands in stress-induced antinociception in male mice.
Swimming at 21 degrees C for 3 min induced antinociceptive effects in male mice with all animals showing a significant increase in response time to the hot plate test measured 10 min after swimming. This antinociceptive activity was still evident at 20 min after swimming. Prior administration of the GABAB receptor agonist, baclofen, potentiated the swimming-induced antinociception. For the group receiving the higher dose of baclofen (2.0 mg/kg, s.c.) the potentiation was still evident 40 min postswimming. However, prior administration of CGP-35348, a GABAB receptor antagonist, had no effect on the antinociceptive activity observed after swimming. Restraint for 1 h also induced significant antinociceptive activity in male mice. This restraint-induced antinociceptive activity was enhanced by prior administration of baclofen and was completely abolished by the administration of CGP-35348 before restraint. The present findings suggest that GABAB receptors may play a role in stress-induced antinociception and different GABAB receptor subtypes may be involved depending on the nature of the stress.
Houston
A J
AJ
Neuropharmacology Research Group, School of Pharmacy and Biomedical Science, University of Portsmouth, Hampshire, UK.
Wong
J C
JC
Ebenezer
I S
IS
D000698:Analgesia; D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D018080:Receptors, GABA-B / Q000502:physiology*; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000503:physiopathology*; D013550:Swimming
D018755:GABA Agonists; D018756:GABA Antagonists; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D009943:Organophosphorus Compounds; D018080:Receptors, GABA-B; C066430:CGP 35348; D001418:Baclofen