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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-7-10
pubmed:abstractText
The specific opioid receptor antagonist naloxone modifies the effects of amphetamine in a wide variety of behavioral paradigms. Naloxone also attenuates the amphetamine-induced increase in extracellular dopamine in the brain of rats. Therefore, these experiments were designed to replicate the neurochemical and behavioral interactions between naloxone and amphetamine, and to extend these observations to interactions between naloxone and cocaine. Microdialysis was performed on adult male rats of Sprague-Dawley descent. Rats were pretreated with a subcutaneous injection of 5.0 mg/kg naloxone or vehicle, which was followed 30 min later by cumulative doses of subcutaneous d-amphetamine (0.0, 0.1, 0.4, 1.6, 6.4 mg/kg) or intraperitoneal cocaine (0, 3, 10, 30, 56 mg/kg) at 30 min intervals. The microdialysis probes were perfused at a flow rate of 0.6 microliter/min with artificial cerebrospinal fluid. Dialysate samples were collected every 10 min from either the nucleus accumbens or striatum and analyzed for dopamine content by high-performance liquid chromatography (HPLC). Locomotor activity (photobeam breaks) was monitored simultaneously with the collection of dialysate samples. Amphetamine and cocaine dose-dependently increased extracellular dopamine in both the nucleus accumbens and striatum. Naloxone pretreatment significantly reduced the amphetamine-induced increase in extracellular dopamine in both brain regions and also attenuated the increase in locomotor activity elicited by amphetamine. Naloxone pretreatment had no effect, however, on the cocaine-induced increase in extracellular dopamine or locomotor activity. These findings suggest that endogenous opioid systems play a role in mediating the neurochemical and behavioral effects of amphetamine, but not those of cocaine.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:day
24
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9-16
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Naloxone reduces the neurochemical and behavioral effects of amphetamine but not those of cocaine.
pubmed:affiliation
Department of Pharmacology, Emory University, Atlanta, GA 30322, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.