Involvement of delta-opioid receptors in the effects of morphine on locomotor activity and the mesolimbic dopaminergic system in mice.
Naltrindole (NTI) and naltriben (NTB), a benzofuran derivative of NTI, were recently synthesized as highly selective delta-opioid receptor antagonists. Both NTI and NTB failed to suppress the antinociceptive effect induced by morphine. In contrast, both NTI and NTB significantly suppressed the morphine-induced hyperlocomotion and increase in turnover of dopamine (DA) in the mouse limbic forebrain. These results suggest that delta-opioid receptors play, at least in part, a role in the morphine-induced hyperlocomotion and excitation of mesolimbic DA systems, but not antinociception.
Narita
M
M
Department of Pharmacology, School of Pharmacy, Hoshi University, Tokyo, Japan.
Suzuki
T
T
Funada
M
M
Misawa
M
M
Nagase
H
H
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D004298:Dopamine / Q000378:metabolism / Q000502:physiology*; D006719:Homovanillic Acid / Q000378:metabolism; D008032:Limbic System / Q000187:drug effects*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D004856:Postural Balance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects; D017465:Receptors, Opioid, delta / Q000037:antagonists & inhibitors / Q000187:drug effects*
D000700:Analgesics; D009292:Narcotic Antagonists; D017465:Receptors, Opioid, delta; D015102:3,4-Dihydroxyphenylacetic Acid; C068868:naltrindole benzofuran; D009271:Naltrexone; D009020:Morphine; C055382:naltrindole; D004298:Dopamine; D006719:Homovanillic Acid