Effects of buspirone on the immune response to stress in mice.

Several experiments were conducted to evaluate the effects of buspirone, a selective 5-hydroxytryptamine-1A (5-HT1A) anxiolytic, on the immune system of mice exposed to a chronic auditory stressor. Daily injection with 0.5 and 1 mg/kg (intraperitoneally) of buspirone resulted in a dose-dependent reduction in the stress-induced suppression of the natural killer (NK) cell activity and the in vitro and in vivo activity of phagocytosis. Higher doses of buspirone (2.0 mg/kg) showed less robust immunoenhancing effects in stressed mice, and caused a significant suppression of these immune parameters in unstressed mice.