In vivo monoamine release during naloxone-precipitated morphine withdrawal.
There is much evidence from animal work suggesting that the release of noradrenaline (NA) in the brain increases during naloxone-precipitated morphine withdrawal, but the evidence in favour of changes in release of 5-hydroxytryptamine (5-HT) and dopamine (DA) is contradictory. Here we demonstrate, using in vivo microdialysis, that whilst there is a considerable increase (300%) in release of NA in hippocampus precipitated by naloxone in morphine-dependent rats, there is no change in the release of either 5-HT (in hippocampus) or DA (in nucleus accumbens). These results are consistent with suggestions that the symptoms of morphine withdrawal in rats are due primarily to an increase in central NA release.
Silverstone
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PH
MRC Unit, Radcliffe Infirmary, Oxford, UK.
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D000818:Animals; D003956:Dialysis; D004298:Dopamine / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism; D008297:Male; D009020:Morphine / Q000009:adverse effects*; D009270:Naloxone / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D013375:Substance Withdrawal Syndrome / Q000378:metabolism*
D012701:Serotonin; D009270:Naloxone; D009020:Morphine; D004298:Dopamine; D009638:Norepinephrine