English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Psychomotor stimulants and mu opioid agonists are often used together by polydrug abusers, and it has been suggested that this form of polydrug abuse may result from the ability of stimulants and mu agonists to enhance each other's abuse-related effects. To investigate this possibility, the present study examined stimulant-opioid interactions in rhesus monkeys trained to discriminate cocaine. Specifically, the effects of the mu opioid agonists heroin, alfentanil, fentanyl, and morphine administered alone or in combination with cocaine or d-amphetamine were examined in five monkeys trained to discriminate 0.4 mg/kg cocaine (IM) from saline in a two-lever, food-reinforced drug discrimination procedure. When administered alone, the rapid onset mu agonists heroin (0.032-0.32 mg/kg) and alfentanil (0.01-0.1 mg/kg) substituted completely for cocaine in three of five monkeys but produced primarily saline-appropriate responding in the other two monkeys. The slower onset mu agonists fentanyl (0.0056-0.056 mg/kg) and morphine (0.56-10 mg/kg) substituted for cocaine in only one of five monkeys. When administered as pretreatments to cocaine, morphine and fentanyl increased levels of cocaine-appropriate responding produced by low doses of cocaine in some monkeys. Morphine pretreatment also increased levels of cocaine-appropriate responding produced by low doses of amphetamine in some monkeys. However, in other monkeys, morphine and fentanyl pretreatment did not alter the discriminative stimulus effects of cocaine or amphetamine. These results indicate that there are substantial individual difference in the effects of mu agonists in cocaine-discriminating rhesus monkeys. In some monkeys, mu agonists mimic or enhance the discriminative stimulus of cocaine, whereas in other monkeys, mu agonists neither mimic nor enhance the effects of stimulants.

Effects of Mu Opioid Agonists Alone and in Combination with Cocaine and D-Amphetamine in Rhesus Monkeys Trained to Discriminate Cocaine