Mediation of swim-stress antinociception by the opioid delta 2 receptor in the mouse.
The present study has characterized the antinociceptive response to cold water swim-stress (CWSS) in mice using opioid-selective antagonists as well as tolerance and cross-tolerance approaches. Mice subjected to CWSS using water at 5 degrees C for 3 min showed a marked antinociceptive response in the tail-flick test, which reached approximately 90% after +10 min, and which persisted for 15 to 20 min. This antinociceptive response (at +10 min) was antagonized by naloxone or by the delta antagonist ICI 174,864. Additionally, the CWSS response was antagonized by the opioid delta 2 antagonist, naltrindole-5'-isothiocyanate, but not by the delta 1 antagonist, [D-Ala2,Leu5,Cys6]enkephalin, or by the mu antagonist, beta-funaltrexamine or by the kappa antagonist, norbinaltorphimine. Although the CWSS-induced antinociceptive effect was blocked by some delta antagonists and tolerance resulted from the CWSS-induced response, the decrease in body temperature after each CWSS exposure was not affected by the opioid antagonists and reliably occurred in CWSS-tolerant mice, suggesting that the observed antinociception was independent of changes in body temperature. In mice rendered tolerant to the antinociceptive actions of the mu agonist, [D-Ala2,NMPhe4,Gly-ol] enkephalin, or to [D-Pen2,D-Pen5]enkephalin (predominantly a delta 1 agonist), the CWSS-induced antinociceptive response was unaltered. In contrast, in mice tolerant to the delta 2 agonist, [D-Ala2,Glu4]deltorphin, the CWSS-induced antinociceptive response was markedly and significantly reduced.(ABSTRACT TRUNCATED AT 250 WORDS)
Vanderah
T W
TW
Department of Pharmacology, University of Arizona Health Sciences Center, Tucson.
Wild
K D
KD
Takemori
A E
AE
Sultana
M
M
Portoghese
P S
PS
Bowen
W D
WD
Mosberg
H I
HI
Porreca
F
F
D000698:Analgesia; D000818:Animals; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives* / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009292:Narcotic Antagonists / Q000494:pharmacology*; D005082:Physical Exertion; D011957:Receptors, Opioid / Q000187:drug effects*; D017465:Receptors, Opioid, delta; D013550:Swimming
D009292:Narcotic Antagonists; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D004743:Enkephalin, Leucine; C040643:N,N-diallyl-tyrosyl-alpha-aminoisobutyric acid-phenylalanyl-leucine