Serotonin-induced platelet intracellular Ca2+ responses in untreated depressed patients and imipramine responders in remission

• Published in: Biological psychiatry (1969) 1999-04, Vol.45 (8), p.1042-1048
• Main Authors: Tomiyoshi, Rika, Kamei, Kenji, Muraoka, Shinichiro, Muneoka, Katsumasa, Takigawa, Morikuni
• Format: Article
• Language: English
• Subjects: Adult; Adult and adolescent clinical studies; Antidepressive Agents, Tricyclic - therapeutic use; Biological and medical sciences; Blood Platelets - drug effects; Blood Platelets - metabolism; Ca2; Calcium - metabolism; Depression; Depressive Disorder, Major - diagnosis; Depressive Disorder, Major - drug therapy; Female; Humans; imipramine; Imipramine - therapeutic use; Intracellular Membranes - drug effects; Intracellular Membranes - metabolism; Male; Medical sciences; Mood disorders; platelet; Psychiatric Status Rating Scales; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; remission; Remission Induction; serotonin; Serotonin - pharmacology; Severity of Illness Index; Treatment Outcome
• ISSN: 0006-3223; 1873-2402
• DOI: 10.1016/S0006-3223(98)00171-1

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 Ca2+-sensitive fluorescent probe fura-2. Results: The increases in intracellular free Ca2+ concentration in platelets induced by stimulation with serotonin (5-HT) ([Ca2+]Δ) 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+]Δ. 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.