Modulation of proorphaninFQ/N gene expression by morphine in the rat mesocorticolimbic system.
We studied the effects of acute and chronic morphine treatment on proorphaninFQ/N (proOFQ/N) gene expression in the mesocorticolimbic system, known to be a reward-relevant area, of the rat CNS. Northern blot analysis revealed that a single injection of morphine 10 mg/kg i.p. increased proOFQ/N mRNA levels in nucleus accumbens, temporo-parietal cortex and in striatum. The chronic administration of the opiate caused a significant increase of proOFQ/N mRNA levels in the ventral tegmental area and a decrease in the striatum and in the nucleus accumbens. No changes were observed in the prefrontal cortex. These data indicate for the first time that morphine alters proOFQ/N gene expression in mesocorticolimbic areas, supporting the direct interaction between the opioid and OFQ/N systems and the OFQ/N involvement in morphine-rewarding mechanisms.
Romualdi
Patrizia
P
Department of Pharmacology, University of Bologna, via Irnerio 48, 40126 Bologna, Italy.
Landuzzi
Daniela
D
D'Addario
Claudio
C
Candeletti
Sanzio
S
D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects* / Q000502:physiology; D004334:Drug Administration Schedule; D015870:Gene Expression / Q000187:drug effects* / Q000502:physiology; D008032:Limbic System / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008636:Mesencephalon / Q000187:drug effects* / Q000502:physiology; D009020:Morphine / Q000494:pharmacology*; D011498:Protein Precursors / Q000502:physiology*; D012333:RNA, Messenger / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011957:Receptors, Opioid / Q000502:physiology*
D000701:Analgesics, Opioid; D011498:Protein Precursors; D012333:RNA, Messenger; D011957:Receptors, Opioid; C119224:pronociceptin; D009020:Morphine