Neurotrophins rescue cerebellar granule neurons from oxidative stress-mediated apoptotic death: selective involvement of phosphatidylinositol 3-kinase and the mitogen-activated protein kinase pathway

J Neurochem. 1998 May;70(5):1859-68. doi: 10.1046/j.1471-4159.1998.70051859.x.


Cerebellar granule neurons maintained in medium containing serum and 25 mM K+ reliably undergo an apoptotic death when switched to serum-free medium with 5 mM K+. New mRNA and protein synthesis and formation of reactive oxygen intermediates are required steps in K+ deprivation-induced apoptosis of these neurons. Here we show that neurotrophins, members of the nerve growth factor gene family, protect from K+/serum deprivation-induced apoptotic death of cerebellar granule neurons in a temporally distinct manner. Switching granule neurons, on day in vitro (DIV) 4, 10, 20, 30, or 40, from high-K+ to low-K+/serum-free medium decreased viability by >50% when measured after 30 h. Treatment of low-K+ granule neurons at DIV 4 with nerve growth factor, brain-derived neurotrophic factor (BDNF), neurotrophin-3, or neurotrophin-4/5 (NT-4/5) demonstrated concentration-dependent (1-100 ng/ml) protective effects only for BDNF and NT-4/5. Between DIV 10 and 20, K+-deprived granule neurons showed decreasing sensitivity to BDNF and no response to NT-4/5. Cerebellar granule neuron death induced by K+ withdrawal at DIV 30 and 40 was blocked only by neurotrophin-3. BDNF and NT-4/5 also circumvented glutamate-induced oxidative death in DIV 1-2 granule neurons. Granule neuron death caused by K+ withdrawal or glutamate-triggered oxidative stress was, moreover, limited by free radical scavengers like melatonin. Neurotrophin-protective effects, but not those of antioxidants, were blocked by selective inhibitors of phosphatidylinositol 3-kinase or the mitogen-activated protein kinase pathway, depending on the nature of the oxidant stress. These observations indicate that the survival-promoting effects of neurotrophins for central neurons, whose cellular antioxidant defenses are challenged, require activation of distinct signal transduction pathways.

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Brain-Derived Neurotrophic Factor / pharmacology
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism
  • Cell Death / drug effects
  • Cells, Cultured
  • Cellular Senescence / physiology
  • Cerebellum / cytology
  • Cerebellum / drug effects*
  • Cerebellum / physiology
  • Glutamic Acid / pharmacology
  • Nerve Growth Factors / pharmacology*
  • Neurons / drug effects*
  • Neurons / physiology
  • Oxidative Stress / physiology*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Potassium Deficiency / physiopathology
  • Rats
  • Rats, Sprague-Dawley


  • Brain-Derived Neurotrophic Factor
  • Nerve Growth Factors
  • neurotrophin 5
  • Glutamic Acid
  • Phosphatidylinositol 3-Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases
  • neurotrophin 4