Related Experiment Videos
Dextromethorphan and dextrorphan in rats: common antitussives--different behavioural profiles
M Dematteis1, G Lallement, M Mallaret
1Unité de Neuropharmacologie, CRSSA, La Tronche, France.
Fundamental & Clinical Pharmacology
|October 30, 1998
Summary
Dextromethorphan (DM) and its metabolite dextrorphan (DX) show different behavioral effects in rats. While DM has sedative effects, DX exhibits phencyclidine (PCP)-like effects, raising concerns for high-dose DM use.
Area of Science:
- Neuroscience
- Pharmacology
- Behavioral Science
Background:
- Dextromethorphan (DM), an antitussive, is explored for antiepileptic and neuroprotective uses.
- Higher doses for new indications may cause phencyclidine (PCP)-like side effects due to conversion to dextrorphan (DX).
- DX is a potent NMDA receptor antagonist, more so than DM.
Purpose of the Study:
- To compare the behavioral effects of DM and DX in rats.
- To assess motor activity, learning, and memory impacts of DM and DX administration.
Main Methods:
- Rats received intraperitoneal injections of DM and DX at various doses.
- Motor activity was evaluated using an open field test.
- Learning and memory were assessed via the Morris water maze.
Main Results:
- DM decreased locomotion and stereotyped behavior; DX increased them, both with ataxia.
- DX (10-15 mg/kg) impaired spatial learning, while DM (10-30 mg/kg) did not.
- DX showed minor working memory impairment at 15 mg/kg; neither drug affected reference memory.
Conclusions:
- DM and DX exhibit distinct behavioral profiles: sedative for DM, PCP-like for DX.
- PCP-like side effects from DM are possible at high doses or in susceptible individuals via DX conversion.
- Monitoring DM metabolism and adjusting prescriptions can mitigate adverse effects.