W. Asakura et al., REM-SLEEP DEPRIVATION POTENTIATES THE EFFECTS OF IMIPRAMINE AND DESIPRAMINE BUT NOT THAT OF CLOMIPRAMINE IN THE FORCED SWIMMING TEST, Japanese Journal of Pharmacology, 63(4), 1993, pp. 455-460
Effects of REM sleep (REMs) deprivation on the basal swimming activity
and the tricyclic antidepressants-induced increase in swimming activi
ty in the forced swimming test were investigated. Immediately after a
48-hr period of REMs deprivation, the basal swimming activity in REMs-
deprived mice was significantly higher than those in group-housed and
socially isolated animals used as the control groups. The REMs depriva
tion-induced increase in the swimming activity was not changed by adre
noceptor antagonists and it returned to the control levels 3 hr after
the REMs deprivation treatment. Moreover, imipramine and desipramine b
ut not clomipramine further increased the swimming activity enhanced b
y REMs deprivation at doses that did not affect the activity in the co
ntrol groups. The enhancing effect of REMs deprivation on the sensitiv
ity to imipramine and desipramine remained unchanged even at 3 hr afte
r the REMs deprivation treatment, and it was blocked by the alpha(2)-a
drenoceptor antagonist yohimbine. These results suggest that the REMs
deprivation-induced increase in basal swimming activity in the forced
swimming test is not mediated by adrenoceptor mechanisms, whereas the
enhancing effect of REMs deprivation on the sensitivity to imipramine
and desipramine may be mediated by the functional changes in alpha(2)-
adrenoceptors in the brain.