Withdrawal from chronic morphine administration causes prolonged enhancement of immobility in rat forced swimming test
Anraku T, Ikegaya Y, Matsuki N, Nishiyama N.
Laboratory of Chemical Pharmacology,
Graduate School of Pharmaceutical Sciences,
University of Tokyo, Japan.
Psychopharmacology (Berl) 2001 Sep;157(2):217-20


RATIONALE: Opiate-dependent subjects experience severe depression as one of the subjective symptoms during withdrawal. No experimental work, however, has focused on the ability of opiate-withdrawal to produce depression-like behavior in dependent animal. OBJECTIVES. We therefore investigated whether withdrawal from chronic morphine treatment affects immobility in forced swimming test in rats. METHODS: Morphine was administered in a dose escalation fashion using doses ranging from 20 to 140 mg/kg twice daily for 14 days, followed by 1-6 days of withdrawal, and their duration of immobility was assessed. RESULTS: After the last morphine treatment. an increase in immobility occurred late on day 3 and persisted to at least day 6 of withdrawal without any change in ambulatory activity. CONCLUSIONS: The results suggest that the morphine withdrawal resulted in prolonged enhancement of depression-like behavior in drug-dependent laboratory animals.
Drugs versus cash
Morphine: structure
Morphine and magnesium
Is morphine a smart drug?
Morphine as an antipsychotic?
Is morphine an antidepressant?
Depression, opioids and the HPA
Morphine and the urge to explore
Morphine for endogenous depressives
Tolerance, sensitization and dependence
Depressed laboratory rats and drug policy
Opioids, depression and learned helplessness

and further reading

Future Opioids
BLTC Research
Utopian Surgery?
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World

The Good Drug Guide
The Good Drug Guide

The Responsible Parent's Guide
To Healthy Mood Boosters For All The Family