EFFECT OF SEROTONIN ON CYTOKINE MESSENGER-RNA EXPRESSION IN RAT HIPPOCAMPAL ASTROCYTES

Serotonin is a widely distributed neurotransmitter which elicits a ran ge of central activities. We examined the effect of serotonin on cytok ine mRNA expression by rat hippocampal astrocytes in primary cultures. Semi-quantitative reverse transcription-polymerase chain reaction (RT -PCR) analysis shows that interleukin-6 (IL6) mRNA is expressed after 10(-12) M serotonin stimulation whereas transforming growth factor-bet a (TGF beta) and tumor necrosis factor (TNF alpha) are induced by 10(- 10) M serotonin. These inductions appeared after 1 h stimulation for I L6 and TNF alpha, whereas that of TGF beta appeared after 4 h. The pre sent results provide the first evidence that serotonin can influence a strocyte cytokine production, and thus this neurotransmitter may be co nsidered a potential neuroimmunomodulator.