Morphine pretreatment reduces clomipramine effect in mouse forced-swimming test.

It had previously been shown that naloxone inhibits the effect of clomipramine both in a pain test in the forced-swimming test in mice which is proposed as an antidepressant study model. Evidence is reported of a decrease in activity of clomipramine in the forced-swimming test in mice after morphine pretreatment. The hypothesis of an interaction with mu-opiate receptors is considered.