Serotonin 5-HT2 receptor binding on blood platelets--a peripheral marker for depression?
Several methods of platelet membrane preparation and binding conditions were screened in order to optimize the labeling of serotonergic 5-HT2 receptors on previously frozen human platelet membranes with tritiated ketanserin. Under optimal conditions, 5-HT2 receptors in normal subjects (5 males, 7 females, age range 21 to 71) have a Kd of 1.5 +/- 0.2 nM and a Bmax of 33.9 +/- 5.3 fmole/mg protein. In a group of patients with major depressive disorder exactly matched for age and sex with the normal control group, we find a significant increase in receptor density, to 66.8 +/- 11.4 fmole/mg, with no significant change in the affinity (2.3 +/- 0.5 nM). Four weeks of treatment with antidepressant drugs result in a significant decrease of Bmax, down to control levels (29.4 +/- 3.9). Thus, ketanserin can be used to monitor changes in platelet serotonin 5-HT2 receptors which may be a relevant marker for the state of depression.
Biegon
A
A
Weizmann Institute of Science, Rehovot, Israel.
Weizman
A
A
Karp
L
L
Ram
A
A
Tiano
S
S
Wolff
M
M
D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D019411:Clinical Laboratory Techniques; D003866:Depressive Disorder / Q000097:blood / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011985:Receptors, Serotonin / Q000378:metabolism*; D012016:Reference Values; D012701:Serotonin / Q000097:blood*
D011985:Receptors, Serotonin; D012701:Serotonin