Effects of ciliary neurotrophic factor on excitotoxicity and calcium-ionophore A23187-induced cell death in cultured embryonic striatal neurons

Ciliary neurotrophic factor (CNTF) has a protective effect on the striatum in animal models of Huntington's disease. However, the mechanism through which it exerts its effect is not clear. In this study, we show that there is a concentration-dependent direct protective effect of CNTF against N-methyl-D-aspartate-mediated excitotoxicity on striatal neurons in vitro. The CNTF has to be added more than half an hour before the insult for the effect to occur and its effect is eliminated by the presence of the protein synthesis inhibitor cycloheximide. This suggests that the protective mechanism of CNTF does not involve acute interference with the glutamate receptors, but probably requires gene/protein expression. We have also shown that the effect of CNTF against glutamate-induced excitotoxicity is dependent on the concentration of glutamate with a protective effect more evident at a low grade excitotoxic insult. Finally, we saw no effect of CNTF on calcium ionophore A23187-induced toxicity in striatal cultures, indicating that the growth factor does not promote survival by enhancing general defenses against raised intracellular levels of calcium (C) 1999 Academic Press.