Delta opioid antagonist, 16-Me cyprenorphine, selectively attenuates conditional fear- and DPDPE-induced analgesia on the formalin test. Pharmacol Biochem Behav 1989 Feb;32(2):469-73
Date
02/01/1989Pubmed ID
2542994DOI
10.1016/0091-3057(89)90181-0Scopus ID
2-s2.0-0024345534 (requires institutional sign-in at Scopus site) 25 CitationsAbstract
The effects of 16-Me cyprenorphine (M80) on the antinociception produced by reexposing rats to a chamber associated with footshock (1 mA, 0.75 sec) 24 hr earlier was assessed with the formalin test. In Experiment 1, intracerebroventricular administration of M80 dose-dependently (0.5-8 micrograms) reversed conditional analgesia. Experiment 2 demonstrated that M80 (5 micrograms) had no effect on baseline pain sensitivity, but completely reversed conditional analgesia. Experiment 3 demonstrated that 0.25 micrograms DAGO, 3.5 micrograms DPDPE, and 28 micrograms U50,488H all produced equivalent levels of antinociception on the formalin test. The 5 micrograms dose of M80 completely reversed the antinociception produced by DPDPE but did not influence that produced by DAGO or U50,488H. These data suggest, that at the doses employed, M80 is a selective delta-opioid receptor antagonist and that delta-receptors are involved in conditional fear-induced analgesia.
Author List
Fanselow MS, Calcagnetti DJ, Helmstetter FJAuthor
Fred Helmstetter PhD Professor in the Psychology / Neuroscience department at University of Wisconsin - MilwaukeeMESH terms used to index this publication - Major topics in bold
3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-IsomerAnalgesics
Animals
Conditioning, Operant
Enkephalin, D-Penicillamine (2,5)-
Enkephalins
Fear
Female
Formaldehyde
Injections, Intraventricular
Morphinans
Pain Measurement
Pyrrolidines
Rats
Receptors, Opioid
Receptors, Opioid, delta
