Abstract
Nociceptin/orphanin FQ (N/OFQ) is a neuropeptide that exerts antiopiate effects under some circumstances, and there is evidence that it contributes to opiate tolerance. This raises the question, might N/OFQ also contribute to opiate dependence and abstinence? Twenty-two male Sprague-Dawley rats were cannulated in the third ventricle and challenged 7 days later by third ventricle injection of 50, 200 or 1,000 ng N/OFQ or saline alone. Each rat was observed under 'blind' conditions for 30 min beginning 15 min after onset of the third ventricle injection. There was a significant positive linear trend of signs as a function of N/OFQ dose. Subjects receiving saline had 18.0±2.0 (mean±SEM) overall abstinence-like signs, whereas subjects receiving 50, 200 or 1000 ng N/OFQ had 3.5.2±3.6, 49.8±2.6 and 63.5±9.7 signs, respectively. In 16 additional rats, abstinence-like signs induced by 1000 ng N/OFQ were significantly attenuated by low SC doses of morphine or clonidine. These results raise the possibility that N/OFQ might contribute to opiate dependence and subsequent abstinence syndrome. On the other hand, N/OFQ over a wide dose range induced abstinence signs with similar potency in morphine dependent and non-dependent rats.
Original language | English (US) |
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Pages (from-to) | 344-350 |
Number of pages | 7 |
Journal | Psychopharmacology |
Volume | 151 |
Issue number | 4 |
DOIs | |
State | Published - 2000 |
Keywords
- Antiopiate peptides
- Morphine
- Nociceptin
- Opiate abstinence syndrome
- Opiate dependence
- Orphanin
ASJC Scopus subject areas
- Pharmacology