Prefrontal cortex serotonin, stress, and morphine-induced nucleus accumbens dopamine.
Uncontrollable, but not controllable, stress produces a persistent potentiation of morphine-induced nucleus accumbens dopamine (DA) efflux and morphine-induced medial prefrontal cortex serotonin (5-HT) efflux. Here we investigate medial prefrontal cortex 5-HT mediation of this potentiation. Male Sprague-Dawley rats received bilateral medial prefrontal cortex microinjections of the neurotoxin 5,7-dihydroxytriptamine (5,7-DHT, 8 microg/microl/side), which selectively depleted medial prefrontal cortex 5-HT, or vehicle (Sham), and cannula implantation in the nucleus accumbens shell. After 2 weeks, rats received either uncontrollable stress or no stress. Microdialysis and morphine (3 mg/kg) treatment were performed the following day. Morphine produced an enhanced increase in DA in the Stress-Sham group that was completely blocked by 5,7-DHT lesions, suggesting that 5-HT in the medial prefrontal cortex mediates this potentiation.
Bland
Sondra T
ST
Department of Psychology and Center for Neuroscience, Campus Box 345, University of Colorado, Boulder, CO 80309-0345, USA. sondra.bland@colorado.edu
Schmid
Megan J
MJ
Watkins
Linda R
LR
Maier
Steven F
SF
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001923:Brain Chemistry; D004298:Dopamine / Q000378:metabolism*; D004563:Electrochemistry; D008297:Male; D017551:Microdialysis / Q000379:methods; D008845:Microinjections / Q000379:methods; D009020:Morphine / Q000494:pharmacology*; D009714:Nucleus Accumbens / Q000187:drug effects* / Q000378:metabolism; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D018490:Serotonin Agents / Q000494:pharmacology; D013312:Stress, Physiological / Q000378:metabolism*
D000701:Analgesics, Opioid; D018490:Serotonin Agents; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D009020:Morphine; D004298:Dopamine