The effects of histamine and interleukin-6 on NGF release from cortical astrocytes in primary culture

The influence of neurotransmitter histamine and cytokine interleukin-6 (IL-6) on nerve growth factor (NGF) release was studied in rat neonatal cortical astrocytes in primary culture. Exposure of astrocytes to either histamine or IL-6 resulted in the stimulation of NGF release. Maximal stimulation of NGF release was obtained using histamine at concentration 100 nM after 24 h of treatment (2.3 fold increase over the basal secretion from the control cells). IL-6 (30 ng/ml) induced NGF secretion was 1.66 fold over the basal level. Time course of NGF release, after histamine or IL-6 treatment, showed elevation of NGF level in the culture medium after 8 h or 24 h, respectively. IL-6 antibody effectively blocked the IL-6 stimulatory effect on NGF release, but did not influence NGF release, evoked by histamine. IL-6 antibody alone did not show any influence on NGF release. Our results suggest that IL-6 and histamine stimulate release of NGF by two different and independent molecular pathways.