Decreased serotonin transporter binding in unaffected relatives of manic depressive patients.
BACKGROUND
There are numerous reports of decreased binding to platelet serotonin transporter (5-HTT) in depression, suggesting that it might be considered a trait marker of depression. To further investigate whether reduced 5-HTT function could be an endophenotype in manic depressive illness, we looked for abnormalities of platelet 5-HTT among subjects who are potential carriers of genetic vulnerability to manic depressive illness (MDI).


METHODS
Blood samples were obtained from 20 unaffected relatives from families with at least two individuals with bipolar disorder and from 19 control participants. Plasma 5-HIAA, platelet 5-HT, and [3H] imipramine binding were measured.


RESULTS
Unaffected relatives manifested lower platelet 5-HTT function than control participants as revealed both by reduced number and diminished affinity of imipramine binding sites and diminished platelet 5-HT content.


CONCLUSIONS
These preliminary results suggest that reduced 5-HTT function could be considered a trait marker or an endophenotype in MDI.
Leboyer
M
M
CNRS UMR 7593, Paris, France.
Quintin
P
P
Manivet
P
P
Varoquaux
O
O
Allilaire
J F
JF
Launay
J M
JM
D018759:Adrenergic Uptake Inhibitors / Q000097:blood; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001714:Bipolar Disorder / Q000097:blood* / Q000235:genetics*; D001792:Blood Platelets / Q000378:metabolism; D002352:Carrier Proteins / Q000097:blood* / Q000235:genetics; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000097:blood*; D007099:Imipramine / Q000097:blood; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood* / Q000235:genetics; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D010641:Phenotype; D010865:Pilot Projects; D012701:Serotonin / Q000097:blood* / Q000235:genetics; D050486:Serotonin Plasma Membrane Transport Proteins
D018759:Adrenergic Uptake Inhibitors; D015415:Biomarkers; D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D007099:Imipramine