Abstract: Aim Effects of nerve growth factor (NGF) on intracellular free Ca²⁺ concentration ([Ca²⁺ ]_i) in isolated brain cells of neonatal rat were observed. Methods [Ca²⁺ ]_i was measured with Ca²⁺ sensitive fluorescent indicator, Fura-2/AM, in isolated brain cells of neonatal rat, and the effects of nerve growth factor (NGF)on the changes in [Ca²⁺ ]_i induced by glutamate (Glu)and hydrogen perioxide (H₂O₂)were studied. Results The resting [Ca²⁺ ]_i was 208 ±22 nmol/L when the brain cells were incubated in Hanks'solution containing Ca²⁺ 1.3nmol/L. NGF did not alter the resting [Ca²⁺ ]_i in brain cells.NGF 1～ 100 μg/L dose-dependently attenuated glutamate (0.5 mmol/L)and hydrogen peroxide (0.05 mmol/L)induced elevation of [Ca²⁺ ]_i by 10%, 18%, 32%, 44%, 62%and 14%, 30%, 39%, 49%, and 65%, respectively, with an IC₅₀ of 42.5 and 27.3μg/L (95%confidence limits:28.1～ 71.5 and 18.1～ 46.5 μg/L).Conclusion These suggest that NGF protect cortical neurons against glutamate toxicity and oxidative in-sults via reducing the elevation of [Ca²⁺ ]_i or stabilizing [Ca²⁺ ]_i level.

Key words: nerve growth factor ;glutamate ;hydrogen peroxide ;Fura-2;intracellular free Ca²⁺