Orphanin FQ reduces morphine-induced dopamine release in the nucleus accumbens: a microdialysis study in rats.
The effects induced by orphanin FQ (OFQ) on morphine-induced dopamine (DA), 3,4-dihydroxyphenilacetic acid (DOPAC) and homovanillic acid (HVA) release in the nucleus accumbens were studied in rats by using microdialysis with electrochemical detection. Morphine administered intraperitoneally (i.p., 2, 5 and 10 mg/kg) dose-dependently increased DA and metabolites release in the nucleus accumbens. OFQ intracerebroventricularly (i.c.v.) administered at doses of 2, 5 and 10 nmol did not change DA and metabolites release in the nucleus accumbens. OFQ (10 nmol) administered i.c.v. 15 min before morphine (5 and 10 mg/kg, i.p.) significantly reduced morphine-induced DA and metabolites release in the nucleus accumbens. These effects suggest that OFQ may regulate the stimulant action linked to morphine-induced DA release in the nucleus accumbens.
Di Giannuario
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Laboratorio di Farmacologia, Istituto Superiore di Sanità, Rome, Italy. dig@iss.it
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D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006719:Homovanillic Acid / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D017551:Microdialysis; D009020:Morphine / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009294:Narcotics / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D018847:Opioid Peptides / Q000008:administration & dosage / Q000494:pharmacology*; D004856:Postural Balance / Q000187:drug effects; D011597:Psychomotor Performance / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D011957:Receptors, Opioid / Q000819:agonists*; D000097629:Nociceptin
D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine; D006719:Homovanillic Acid; D009020:Morphine; D009292:Narcotic Antagonists; D009294:Narcotics; D018847:Opioid Peptides; D011957:Receptors, Opioid; D000097629:Nociceptin