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Published on: June 10, 2013
Acute oxycodone induces the pro-emetic pica response in rats
Vinita R Batra1, Lisa M Schrott
1Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA.
The Journal of Pharmacology and Experimental Therapeutics
|August 31, 2011
Summary
The painkiller oxycodone triggers a pica response, a behavior linked to nausea and vomiting. This effect is mediated by opioid receptors and involves specific brain regions, suggesting a potential mechanism for opioid-induced side effects.
Area of Science:
- Neuroscience
- Pharmacology
- Gastroenterology
Background:
- Oxycodone is a widely used pain reliever.
- Nausea and vomiting are common side effects limiting oxycodone use.
- The pica response, or craving for non-food substances, is linked to gastrointestinal distress.
Purpose of the Study:
- To investigate if oxycodone induces the pica response.
- To explore the role of opioid receptors and neural pathways in oxycodone-induced pica.
- To compare oxycodone's effects with cisplatin, a known emetic agent.
Main Methods:
- Administered oxycodone (15 mg/kg, oral) to rats and measured kaolin intake.
- Used naloxone and a kappa-selective antagonist to assess opioid receptor involvement.
- Examined c-fos activation in the area postrema and nucleus of the solitary tract (NTS) as a marker of neural activity.
Main Results:
- Oxycodone significantly increased kaolin intake and stomach wet weight, indicating pica.
- The pica response was mediated by opioid receptors, specifically the mu-opioid receptor.
- Oxycodone increased c-fos activation in the area postrema and NTS, similar to cisplatin but with a greater effect at 2 hours.
Conclusions:
- An antinociceptive dose of oxycodone induces the pica response.
- Oxycodone-mediated pica involves the μ-opioid receptor and activation of the area postrema and NTS.
- These findings suggest a potential neural mechanism linking oxycodone to emesis.
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