A study on the involvement of GABAB receptor ligands in stress-induced antinociception in male mice
Houston, A.J.; Wong, J.C.; Ebenezer, I.S.
Methods and Findings in Experimental and Clinical Pharmacology 19(3): 167-171
1997
ISSN/ISBN: 0379-0355 PMID: 9203164 Document Number: 473503
Swimming at 21 degree 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 GABA-B 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 GABA-B 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 GABA-B receptors may play a role in stress-induced antinociception and different GABA-B receptor subtypes may be involved depending on the nature of the stress.