Interleukin-1β and tumor necrosis factor-α co-operatively enhance a novel trophic activity of astrocytes for pontine cholinergic neurons in vitro

Insulin and insulin-like growth factors (IGFs) are the only known trophic factors for pontine cholinergic neurons. The present study revealed that astrocyte-extract pretreated with IL-1β and TNF-α significantly enhanced choline acetyltransferase (ChAT) activity of the pontine neurons in the presence of a supramaximal dose of insulin, while various trophic factors including IGFs failed to increase the ChAT activity under the same culture conditions, suggesting that IL-1β and TNF-α co-operatively enhanced the expression of a novel trophic factor for pontine cholinergic neurons in astrocytes.