Differential modulation of μ- and δ-opioid antinociception by neuropeptide FF receptors in young mice

• Published in: Neuropeptides (Edinburgh) Vol. 31; no. 1; pp. 1 - 7
• Main Authors: Desprat, C, Zajac, J.-M
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.02.1997
• Subjects: Age Factors; Analgesics, Opioid - pharmacology; Animals; Enkephalin, Ala-MePhe-Gly; Enkephalins - pharmacology; Male; Mice; Mice, Inbred Strains; Morphine - pharmacology; Naltrexone - analogs & derivatives; Naltrexone - pharmacology; Narcotic Antagonists - pharmacology; Neuropeptides - pharmacology; Nociceptors - drug effects; Nociceptors - physiology; Oligopeptides - pharmacology; Receptors, Neuropeptide - metabolism; Receptors, Opioid, delta - agonists; Receptors, Opioid, delta - antagonists & inhibitors; Receptors, Opioid, delta - metabolism; Receptors, Opioid, mu - agonists; Receptors, Opioid, mu - antagonists & inhibitors; Receptors, Opioid, mu - metabolism
• ISSN: 0143-4179; 1532-2785
• DOI: 10.1016/S0143-4179(97)90010-X

The ability of neuropeptide FF (NPFF) to modulate μ- and δ-opioid-induced analgesia by intracerebroventricular administration was compared in adults and 14-day-old mice. In adults, opioid-induced analgesia was predominantly mediated by μ-receptors whereas μ- and δ-receptors were equally involved in pups. An NPFF analog, 1DMe, reduced the analgesic effect of DAGO and [D.Ala 2]deltorphin-I, μ and δ selective agonists respectively. However, a high dose of 1DMe (22 nmol) increased both morphine and [D.Ala 2]deltorphin-I-induced analgesia. Dose—response curves for 1DMe in the presence of naltrindole or naltrexone, δ- and μ-opioid selective antagonists respectively, indicate that 1DMe preferentially reversed μ-receptor-mediated but increased δ-receptor-mediated analgesia. These findings demonstrate differences in control of μ- and δ-induced analgesia by NPFF receptors.