Platelet alpha2-adrenoceptor density in humans: relationships to stress-induced anxiety, psychasthenic constitution, gender and stress-induced changes in the inflammatory response system.
BACKGROUND
This study examined the effects of psychological stress on platelet alpha2-adrenergic receptor (alpha2-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 alpha2-AR antagonist, and the stimulated production of tumor necrosis factor-alpha (TNFalpha), the Th1-like cytokine, interferon-gamma (IFNgamma), 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-2) was used to assess psychasthenia (Scale 7).


RESULTS
Academic examination stress induced a significant increase in alpha2-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 alpha2-AR density. Stress-induced anxiety was accompanied by a pro-inflammatory and Th1-like response, i.e. increased IFNgamma and TNFalpha production. The stress-induced changes in platelet alpha2-AR density were significantly and positively related to the production of TNFalpha, IL-10 and IL-5 and negatively to that of IFNgamma.


CONCLUSIONS
Subchronic psychological stress in humans induces increased alpha2-AR density, which is related to stress-induced anxiety, an anxiety-prone constitution and female sex. Increased alpha2-AR density is accompanied by a Th2-like response and increased TNFalpha production. The results suggest that: (i) alpha2-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 alpha2-ARs, and the IRS, such as Th1/Th2-like functions and the production of TNFalpha.
Maes
M
M
Van Gastel
A
A
Delmeire
L
L
Kenis
G
G
Bosmans
E
E
Song
C
C
D000328:Adult; D001007:Anxiety / Q000276:immunology* / Q000523:psychology; D001143:Arousal / Q000502:physiology*; D001792:Blood Platelets / Q000276:immunology*; D004522:Educational Status; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D008297:Male; D009440:Neurasthenia / Q000276:immunology* / Q000523:psychology; D010555:Personality Inventory; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology*; D013315:Stress, Psychological / Q000150:complications*; D013334:Students / Q000523:psychology; D018418:Th2 Cells / Q000276:immunology
D018836:Inflammation Mediators; D018341:Receptors, Adrenergic, alpha-2