Influence of age, sex and diurnal variability on imipramine receptor binding and serotonin uptake in platelets of normal subjects.
Imipramine (IMI) binding and serotonin (5-HT) uptake were determined in platelets of 98 healthy volunteers; and their association with age, sex and circadian rhythm were evaluated. A large interindividual variability was found for both IMI and 5-HT parameters. There was a negative correlation of IMI affinity constant (Kd) and binding (Bmax) with age, but no such correlation of 5-HT affinity constant (Km) or uptake (Vmax). Significant age-related diurnal variability was found for 5-HT Km in the whole group as well as for IMI Kd in males, but not in females. There was no significant correlation between 5-HT Vmax and IMI Bmax. Our results underscore a cautious approach to the interpretation of platelet serotonergic studies. In light of the multiple variables influencing the results, the usefulness of IMI or 5-HT as clinical markers should be re-evaluated.
Halbreich
U
U
Department of Psychiatry, State University of New York, Buffalo 14215.
Rojansky
N
N
Zander
K J
KJ
Barkai
A
A
D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D000818:Animals; D001792:Blood Platelets / Q000737:chemistry / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins; D002940:Circadian Rhythm; D003866:Depressive Disorder / Q000378:metabolism; D005260:Female; D006801:Humans; D007099:Imipramine / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter / Q000378:metabolism; D011985:Receptors, Serotonin / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D012737:Sex Factors
D002352:Carrier Proteins; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter; D011985:Receptors, Serotonin; C027775:imipramine receptor; D012701:Serotonin; D007099:Imipramine