NEL VOL. 21 No. 5 ORIGINAL ARTICLE Full text pdf (146 kb)
2000; 21:375–382
Negative immunoregulatory effects of noradrenaline through a2-adrenoceptor activation by Michael Maes, Aihua Lin, Gunter Kenis, Belinda Egyed & Eugene Bosmans
BACKGROUND: There are some reports that catecholamines and b-adrenoceptor agonists may suppress some immune functions.
OBJECTIVES: The present study was carried out in order to examine the effects of noradrenaline (10-5 M, 10-6 M and 10-7 M), yohimbine (10-5 M, 10-6 M and 10-7 M), an a2-adrenoceptor antagonist, and clonidine (10-5 M, 10-6 M and 10-7 M), an a2-adrenoceptor agonist, on the stimulated production of interferon-g (IFNg), a pro-inflammatory cytokine, and interleukin-10 (IL-10), an immuno-inhibitory cytokine.
DESIGN: We measured the in vitro production of (IFNg and IL-10 by stimulated, diluted whole blood of 16 normal volunteers. The IFNg/IL-10 production ratio was computed since this ratio reflects the pro- versus anti-inflammatory capacity of the cultured whole blood.
RESULTS: We found that 1) noradrenaline, 10-5 M, 10-6 M, and 10-7 M, significantly suppressed the production of IFNg and that noradrenaline, 10-5 M, significantly enhanced the production of IL-10. Clonidine, 10-5 M and 10-7 M, significantly suppressed the production of IFNg. Noradrenaline, 10-5 M and 10-6 M, and clonidine, 10-5 M, significantly suppressed the IFNg/IL-10 production ratio. There were no significant effects of yohimbine on IFNg or IL-10 production.
CONCLUSIONS: 1) noradrenaline has significant negative immunoregulatory effects in humans through enhancing the production of IL-10 and suppressing that of IFNg; and 2) the suppression of the production of IFNg is in part related to a2-adrenoceptor activation.
