Chronic morphine treatment modulates the extracellular levels of endogenous enkephalins in rat brain structures involved in opiate dependence: a microdialysis study
| Autor: | Florence Noble, Annie Cupo, Jodie Wilson, Bernard P. Roques, Magdalena Mas Nieto |
|---|---|
| Přispěvatelé: | Institut de pharmacologie moléculaire et cellulaire (IPMC), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2002 |
| Předmět: |
Male
Microdialysis Enkephalin Physical dependence Pharmacology Nucleus accumbens Hippocampus Drug Administration Schedule Nucleus Accumbens 03 medical and health sciences 0302 clinical medicine Reward Conditioning Psychological medicine Animals Periaqueductal Gray Rats Wistar Wakefulness ARTICLE Opioid peptide 030304 developmental biology Endogenous opioid Cholecystokinin Brain Chemistry 0303 health sciences Behavior Animal Morphine Chemistry General Neuroscience digestive oral and skin physiology Brain Enkephalins Rats Substance Withdrawal Syndrome Opioid Peptides medicine.symptom Opiate Extracellular Space Morphine Dependence 030217 neurology & neurosurgery hormones hormone substitutes and hormone antagonists |
| Zdroj: | Journal of Neuroscience Journal of Neuroscience, Society for Neuroscience, 2002, 22, pp.1034-1041 |
| ISSN: | 1529-2401 0270-6474 |
| Popis: | The endogenous opioid system is often assumed to play a role in vulnerability to drug abuse. However, controversial results have been reported regarding the levels of enkephalins or preproenkephalin in neurons of rodent brains after opiate administration. The present study was performed to determine the extracellular levels of enkephalins and its physiological antagonist cholecystokinin (CCK), using in vivo microdialysis in freely moving rats after morphine-induced physical dependence or positive place conditioning. A large increase (340%) of Met-enkephalin was observed in the periaqueductal gray matter, a structure involved in morphine withdrawal syndrome, in morphine-dependent rats. No change in CCK immunoreactivity occurred in these conditions. Moreover, using the conditioning place preference paradigm, we observed for the first time opposite changes of enkephalin outflow in the nucleus accumbens (NAc). Thus, an increase in enkephalin levels was observed in rats placed in the drug-associated compartment and a decrease in the saline-paired side. These changes in opioid peptides in the NAc may reflect an "emotional state" of the animals in relation to the expectation of drug reward (reinforcing effects of morphine). Moreover, the lack of regulation in CCK outflow suggests that CCK-opioid interactions in morphine dependence involve probably post-receptor events. |
| Databáze: | OpenAIRE |
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