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Forced-swimming gives mouse continuous stress. Mouse given the stress shows differentstress-coping behaviors, climbing for escaping from the stressful situation and motionlessness forkeeping the physical strength. The former is induced by humoral GalNacα1-3GalNAc-ceramidefractioned with 150 mM NaCl and the latter is done by other humoral lipid fractioned with 100mM NaCl. In the present study, the authors investigate productions of these humoral lipids ofmouse given forced swimming stress in CO2-bubble bathing. GalNacα1-3GalNAc-ceramide reactivitywas increased in serum of mouse given the stress in microbubble CO2 bathing and in serumof mouse given the stress in pressured CO2 bathing. Motionlessness duration was increased inmouse treated with 100 mM NaCl fraction of mouse given the stress in microbubble CO2 bathing,but was not in mouse treated with the fraction of mouse given the stress in pressured CO2bathing. These suggest that CO2 bathing induced stress-coping effect on mice given forcedswimmingstress, and that CO2-bubble form was related to quality of the effect.

International audience; Since depressive patients present alterations in the hypothalamo-pituitary-adrenal (HPA) axis that are normalised by antidepressants, this HPA axis has been considered as a target of their actions. We have investigated the mechanism of action of a cyclohexane extract of Hypericum caprifoliatum (HCP), which displays antidepressant like activity, by studying, in mice, the influence of HCP and of two established antidepressant drugs, imipramine and bupropion, administered either acutely or semi-chronically (once a day, three consecutive days), on serum and brain cortex corticosterone levels, either in basal conditions or shortly after a forced-swimming session (FSS). Administered acutely, imipramine (20 mg/kg, per os (p.o.)), bupropion (30 mg/kg, p.o.) and HCP (360 mg/kg, p.o.) significantly reduced the immobility time and had no effects on FSS-induced increase of serum and cortical corticosterone levels. Conversely, 3 days repeated treatment with imipramine or bupropion resulted in a significant reduction of immobility time and FSS-induced increase of serum and cortical corticosterone levels. In a different way, repeated treatment with HCP significantly reduced the immobility time and only cortical corticosterone levels in stressed mice. These results indicate that short-term treatments with antidepressants are sufficient to induce modifications in the HPA axis reactivity to stress; and that apparently HCP has an influence on corticosterone levels by a mechanism diverse from the other tested antidepressants.