The serotonin-1A receptor distribution in healthy men and women measured by PET and [carbonyl-11C]WAY-100635.
OBJECTIVE
The higher prevalence rates of depression and anxiety disorders in women compared to men have been associated with sexual dimorphisms in the serotonergic system. The present positron emission tomography (PET) study investigated the influence of sex on the major inhibitory serotonergic receptor subtype, the serotonin-1A (5-HT(1A)) receptor.


METHODS
Sixteen healthy women and 16 healthy men were measured using PET and the highly specific radioligand [carbonyl-(11)C]WAY-100635. Effects of age or gonadal hormones were excluded by restricting the inclusion criteria to young adults and by controlling for menstrual cycle phase. The 5-HT(1A) receptor BP(ND) was quantified using (1) the 'gold standard' manual delineation approach with ten regions of interest (ROIs) and (2) a newly developed delineation method using a PET template normalized to the Montreal Neurologic Institute space with 45 ROIs based on automated anatomical labeling.


RESULTS
The 5-HT(1A) receptor BP(ND) was found equally distributed in men and women applying both the manual delineation method and the automated delineation approach. Women had lower mean BP(ND) values in every region investigated, with a borderline significant sex difference in the hypothalamus (p = 0.012, uncorrected). There was a high intersubject variability of the 5-HT(1A) receptor BP(ND) within both sexes compared to the small mean differences between men and women.


CONCLUSIONS
To conclude, when measured in the follicular phase, women do not differ from men in the 5-HT(1A) receptor binding. To explain the higher prevalence of affective disorders in women, further studies are needed to evaluate the relationship between hormonal status and the 5-HT(1A) receptor expression.
Stein
Patrycja
P
Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria.
Savli
Markus
M
Wadsak
Wolfgang
W
Mitterhauser
Markus
M
Fink
Martin
M
Spindelegger
Christoph
C
Mien
Leonhard-Key
LK
Moser
Ulrike
U
Dudczak
Robert
R
Kletter
Kurt
K
Kasper
Siegfried
S
Lanzenberger
Rupert
R
D000328:Adult; D000375:Aging; D005260:Female; D005498:Follicular Phase; D006262:Health; D006801:Humans; D008297:Male; D010879:Piperazines / Q000737:chemistry*; D049268:Positron-Emission Tomography; D011725:Pyridines / Q000737:chemistry*; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism*; D012727:Sex Characteristics; D012923:Social Class
D010879:Piperazines; D011725:Pyridines; D044282:Receptor, Serotonin, 5-HT1A; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide