A PET study of brain 5-HT2 receptors and their correlation with platelet 5-HT2 receptors in healthy humans.
BACKGROUND
Platelets share many properties with brain serotonergic neurons such as active 5-hydroxytryptamine (5-HT) transport, 5-HT2 receptors, and mitochondrial monoamine oxidase.


OBJECTIVE
We measured brain 5-HT2 receptors and platelet 5-HT2 receptors in healthy volunteers to determine if there was any correlation between the two measures.


METHODS
Ten healthy volunteers with no lifetime history of psychiatric illness or family history in first-degree relatives were recruited. 5-HT2 receptor binding was determined for each subject with positron emission tomography and [18F]setoperone scan in the brain and with 3H-LSD binding in platelets.


RESULTS
We found no significant correlation between 5-HT2 binding potential (BP) in platelets (Bmax/Kd) and a semiquantitative estimate of 5-HT2 BP in frontal, parietal, and temporal cortical regions. SPM voxel based analysis also showed no significant correlation between the 5-HT2 BP in platelets and in the brains of the study subjects.


CONCLUSIONS
Brain 5-HT2 receptor binding was not significantly correlated to platelet 3H-LSD binding in healthy subjects. This raises questions about the validity of generalizing findings from platelet studies to 5-HT neurons in the brain.
Yatham
L N
LN
Division of Mood Disorders Clinical Research Unit, The University of British Columbia, Vancouver, Canada. yatham@unixg.ubc.ca
Steiner
M
M
Liddle
P F
PF
Shiah
I S
IS
Lam
R W
RW
Zis
A P
AP
Coote
M
M
D000328:Adult; D001792:Blood Platelets / Q000737:chemistry*; D001923:Brain Chemistry; D005260:Female; D006801:Humans; D008238:Lysergic Acid Diethylamide / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011744:Pyrimidinones / Q000378:metabolism; D011985:Receptors, Serotonin / Q000032:analysis*; D014055:Tomography, Emission-Computed
D011744:Pyrimidinones; D011985:Receptors, Serotonin; D008238:Lysergic Acid Diethylamide; C045359:setoperone