Withdrawal from morphine or amphetamine: different effects on dopamine in the ventral-medial striatum studied with microdialysis.
The effect of withdrawal from chronic morphine or amphetamine treatment on dopamine (DA) neurotransmission in the ventral-medial striatum was studied by use of in vivo microdialysis. There was no effect of 24 h of amphetamine withdrawal on the basal concentration of DA in the ventral-medial striatum. Spontaneous morphine withdrawal (24 h) was associated with a significant decrease in the basal concentration of DA in dialysate, but following morphine replacement and naloxone-precipitated withdrawal variations in withdrawal symptoms were not related to variations in the concentration of DA in dialysate. It is suggested that: (1) the correlation between the extracellular concentration of DA in the ventral-medial striatum and the symptoms of morphine withdrawal may not be indicative of a necessary, causal relationship; and (2) a decrease in the extracellular concentration of DA in the ventral-medial striatum is not a common feature of drug withdrawal syndromes.
Crippens
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Department of Psychology, University of Michigan, Ann Arbor 48104-1687.
Robinson
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D000661:Amphetamine / Q000009:adverse effects*; D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D009020:Morphine / Q000009:adverse effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013375:Substance Withdrawal Syndrome / Q000378:metabolism*
D009020:Morphine; D000661:Amphetamine; D004298:Dopamine