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Repeated treatment with the κ‐opioid agonist U‐69593 increases K + ‐stimulated dopamine release in the rat medial prefrontal cortex
Author(s) -
Fuentealba José Antonio,
Gysling Katia,
Andrés María Estela
Publication year - 2010
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.20808
Subject(s) - dopamine , prefrontal cortex , agonist , neuroscience , opioid , chemistry , anesthesia , pharmacology , medicine , psychology , receptor , cognition , biochemistry
Acute activation of κ‐opioid receptors (KOR) decreases dopamine (DA) extracellular levels in both the medial prefrontal cortex (mPFC) and the nucleus accumbens (NAc). Also, the acute activation of KOR prevents alterations in behavior and neurochemistry occurring after repeated use of psychostimulants. Opposing to the acute effects, repeated administration of the KOR agonist, U‐6593, potentiates both high‐potassium and amphetamine induced DA release in the NAc, suggesting that repeated activation of KOR sensitizes mesolimbic dopaminergic neurotransmission. This study investigated the effect of repeated treatment with U‐69593 on basal and stimulated DA and serotonin (5HT) extracellular levels in the rat mPFC. Rats were injected once daily with U‐69593 (0.16–0.32 mg/kg) or vehicle for 4 days. One day after the last injection, microdialysis experiments assessing DA and 5HT extracellular levels in mPFC were conduced. The repeated treatment with U‐69593 significantly augmented potassium‐stimulated DA extracellular levels, without affecting potassium‐stimulated 5HT extracellular levels, suggesting an increase in DA releasability. Synapse 64:898–904, 2010. © 2010 Wiley‐Liss, Inc.