GT1b ganglioside induces death of dopaminergic neurons in rat mesencephalic cultures

We examined neurotoxicity of GT1b against dopaminergic neurons in vitro. Cu ltures of mesencephalic cells deprived of serum underwent the loss of 19% o f tyrosine hydroxylase immunopositive (TH-ip) neurons. In cultures deprived of serum. treatment with 10-30 mug/ml GT1b attenuated the number of TH-ip neurons by 26-69%, respectively. compared to non-treated cultures. Intrigui ngly, cultures deprived of serum were more vulnerable to GT1b-induced neuro toxicity. Application of 60 mug/ml GT1b to cultures grown in serum containi ng media resulted in the loss of 26% of TH-ip neurons, similar to that (28% ) observed in serum-deprived cultures treated with 10 mug/ml GT1b. Moreover , in our cultures, absence of nitric oxide (NO) production after GT1b treat ment was obvious. The present results strongly suggest direct neurotoxic ac tions of GT1b against dopaminergic neurons regardless of NO. NeuroReport 12 :611-614 (C) 2001 Lippincott Williams & Wilkins.