CYTOSOLIC-FREE [CA2-LYMPHOCYTES FROM DEPRESSED-PATIENTS AND HEALTHY CONTROLS(] IN SINGLE T)

Human lymphocytes are widely used as peripheral models for central neu rones. Alterations in immune function have been reported in depressed patients, e.g. mitogen-induced proliferation is impaired during depres sion. One possible causative mechanism could be altered [Ca2+](i) regu lation. Phytohaemagglutinin (PHA)-induced rise of [Ca2+](i) has been f ound to be diminished in lymphocyte suspensions from depressed patient s. (Ecker et al., this issue). We measured PHA-induced rise of [Ca2+]( i) in single Fura-2 AM-loaded T11(+) lymphocytes of patients with majo r depression and controls to further analyse [Ca2+](i) regulation in d epression. The [Ca2+](i) of resting lymphocytes was 57 +/- 2 nmol/l (m ean +/- SEM). There was no difference in resting [Ca2+](i) of resting lymphocytes of patients and controls. PHA evoked an increase of [Ca2+] (i) an 7 out of 14 cells from control subjects up to 400-500 nmol/l. I n contrast, only 4 out of 13 cells from depressed patients showed an i ncrease of [Ca2+](i) up to 200 nmol/l. In a small fraction of cells fr om both groups the [Ca2+](i) signal is oscillating. Our preliminary da ta confirm alteration of [Ca2+](i) regulation in lymphocytes of depres sed patients.