Serotonin-induced platelet intracellular Ca2+ responses in untreated depressed patients and imipramine responders in remission.
BACKGROUND
Intracellular Ca2+ metabolism in platelets has been investigated as a peripheral marker of affective disorders.


METHODS
We investigated the intracellular free Ca2+ concentration in platelets in both untreated depressed patients with no medications and patients in remission who were treated by imipramine (IMI) (IMI responders) using a Ca(2+)-sensitive fluorescent probe fura-2.


RESULTS
The increases in intracellular free Ca2+ concentration in platelets induced by stimulation with serotonin (5-HT) ([Ca2+] delta) were significantly higher in both the untreated patients and the IMI responders compared with healthy controls; however, there were no significant differences in the basal Ca2+ levels in the platelets ([Ca2+]B) among the three groups. On the other hand, in the IMI responders, we observed positive correlations between the duration of the remission and [Ca2+]B, but not [Ca2+] delta.


CONCLUSIONS
Our present data suggest that the enhancement of 5-HT2A-induced Ca2+ responses persisted after remission in depressed patients, and that the duration of the remission is a factor varying the intracellular basal Ca2+ levels.
Tomiyoshi
R
R
Department of Neuropsychiatry, Kagoshima University Faculty of Medicine, Japan.
Kamei
K
K
Muraoka
S
S
Muneoka
K
K
Takigawa
M
M
D000328:Adult; D000929:Antidepressive Agents, Tricyclic / Q000627:therapeutic use*; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007099:Imipramine / Q000627:therapeutic use*; D007425:Intracellular Membranes / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D011569:Psychiatric Status Rating Scales; D012074:Remission Induction; D012701:Serotonin / Q000494:pharmacology*; D012720:Severity of Illness Index; D016896:Treatment Outcome
D000929:Antidepressive Agents, Tricyclic; D012701:Serotonin; D007099:Imipramine; D002118:Calcium