Psychological Medicine

Platelet [alpha]2-adrenoceptor density in humans: relationships to stress-induced anxiety, psychasthenic constitution, gender and stress-induced changes in the inflammatory response system

M.  MAES  a1 c1, A.  VAN GASTEL  a1, L.  DELMEIRE  a1, G.  KENIS  a1, E.  BOSMANS  a1 and C.  SONG  a1
a1 From the Department of Psychiatry and Neuropsychology, University Hospital of Maastricht, The Netherlands; Clinical Research Center for Mental Health (CRC–MH), Limburg and Eurogenetics Tessenderlo, Belgium; Department of Psychiatry, Vanderbilt University, Nashville, TN, USA; and IRCCS, Brescia, Italy

Medline query on article authors

maes m
van ga
delmeire l
kenis g
bosmans e
song c


Background. This study examined the effects of psychological stress on platelet [alpha]2-adrenergic receptor ([alpha]2-AR) binding sites in relation to stress-induced anxiety and changes in the inflammatory response system (IRS).

Methods. The maximum number of binding sites (Bmax) and their affinity (Kd) for [3H]-rauwolscine, a selective [alpha]2-AR antagonist, and the stimulated production of tumor necrosis factor-[alpha] (TNF[alpha]), the Th1-like cytokine, interferon-[gamma] (IFN[gamma]), and the Th2-like cytokines, interleukin-10 (IL-10) and IL-5, were measured in 35 university students a few weeks before (baseline) as well as on the day before a difficult, oral examination (stress condition). The State-Trait-Anxiety Inventory (STAI)- was recorded during both conditions. The Minnesota Multiphase Personality Inventory (MMPI-2TM) was used to assess psychasthenia (Scale 7).

Results. Academic examination stress induced a significant increase in [alpha]2-AR density in students whose STAI scores increased in the stress period, in female students and in students who scored higher on psychasthenia. There were significant and positive correlations between stress-induced anxiety and changes in [alpha]2-AR density. Stress-induced anxiety was accompanied by a pro-inflammatory and Th1-like response, i.e. increased IFN[gamma] and TNF[alpha] production. The stress-induced changes in platelet [alpha]2-AR density were significantly and positively related to the production of TNF[alpha], IL-10 and IL-5 and negatively to that of IFN[gamma].

Conclusions. Subchronic psychological stress in humans induces increased [alpha]2-AR density, which is related to stress-induced anxiety, an anxiety-prone constitution and female sex. Increased [alpha]2-AR density is accompanied by a Th2-like response and increased TNF[alpha] production. The results suggest that: (i) [alpha]2-AR density is sensitive to graded differences in stress-induced anxiety; and (ii) psychological stress is accompanied by intertwined responses in the catecholaminergic system, such as [alpha]2-ARs, and the IRS, such as Th1/Th2-like functions and the production of TNF[alpha].

c1 Address for correspondence: Professor Michael Maes, Department of Psychiatry and Neuropsychology, University Hospital of Maastricht, Postbus 5800, 6202 AZ Maastricht, The Netherlands.