Caffeic acid produces antidepressive- and/or anxiolytic-like effects through indirect modulation of the alpha 1A-adrenoceptor system in mice.

We previously reported that caffeic acid produce antidepressive- and/or anxiolytic-like effects in two different types of stress models. It has recently been reported that caffeic acid affects the alpha1A-adrenoceptor system. The present study examined whether the alpha1A-adrenoceptor system is involved in the antidepressive- and/or anxiolytic-like effects of caffeic acid. Caffeic acid reduced the duration of immobility and freezing of mice produced by forced swimming and conditioned fear stress, respectively. These effects of caffeic acid were suppressed by the alpha1- and alpha1A-adrenoceptor antagonists. However, caffeic acid did not alter the binding of [3H]prazosin to alpha1A-adrenoceptor in mouse cortical membranes. These results suggest that indirect modulation of the alpha1A-adrenoceptor system may be involved in the antidepressive- and/or anxiolytic-like effects of caffeic acid.