Tyr-W-MIF-1-induced conditioned place preference.
Based on the evidence that Tyr-Pro-Trp-Gly NH2 (Tyr-W-MIF-1) produced dose-dependent, mu-opiate agonistic/antagonistic effects, we investigated whether Tyr-W-MIF- exhibited similar properties in the conditioned place preference (CPP) test. To examine the opiate agonistic effects on CPP, rats were conditioned with alternating ICV injections of saline and Tyr-W-MIF-1 (0 or 200 microg). This procedure resulted in Tyr-W-MIF-1-induced CPP. To examine the opiate antagonistic properties of low doses of Tyr-W-MIF-1, morphine-induced CPP was challenged with Tyr-W-MIF-1 (0, 25, 50, or 100 microg). Morphine-induced CPP was not affected by Tyr-W-MIF-1 at these doses. These findings show that in the CPP test Tyr-W-MIF-1 produced opiate agonistic effects at the high dose and was without opiate antagonistic properties at lower doses.
Nores
W L
WL
Department of Psychology, University of New Orleans, LA 70148, USA. wnores@nba19.med.uth.tmc.edu
Olson
R D
RD
Olson
G A
GA
Vaccarino
A L
AL
Bell
R L
RL
Zadina
J E
JE
Kastin
A J
AJ
D000818:Animals; D002755:Choice Behavior / Q000187:drug effects*; D003213:Conditioning, Psychological / Q000187:drug effects*; D007276:Injections, Intraventricular; D009075:MSH Release-Inhibiting Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017450:Receptors, Opioid, mu / Q000819:agonists*
D009292:Narcotic Antagonists; D017450:Receptors, Opioid, mu; C077532:tyrosyl-prolyl-tryptophyl-glycinamide; D009020:Morphine; D009075:MSH Release-Inhibiting Hormone