Effect of acetylcholine on mitogen response of peripheral lymphocytes isolated from rats exposed to chronic stress

The purpose of this study was to clarify the effects of acetylcholine (Ach) on lymphocyte function in rats under chronic stress. The authors isolated peripheral lymphocytes from rats 5 weeks after stress treatment and then measured interleukin-2 (IL-2) production after stimulation with concanavalin A or phytohemagglutinin-L. Although mitogen-induced IL-2 production of the stress group was lower than that of the control group, the addition of Ach significantly increased mitogen-induced IL-2 production in both groups. This effect of Ach was inhibited by atropine in the control group only. The changes (increasing rates) in mitogen-induced IL-2 production from basal condition showed a negative correlation with serum corticosterone concentrations. The authors observed no correlation between the effects of Ach (changes in mitogen-induced IL-2 production with Ach compared to those without Ach) and serum corticosterone concentration. These findings suggest that stimulation of the parasympathetic nervous system improves lymphocyte function during chronic stress.