Neurotrophic factors and neurodegenerative diseases of the brain

Unlike the neurodegenerative conditions discussed above, diseases such as Alzheimer s and Parkinson s are underlined by the death of CNS neurons. Many of these cells respond to specific 

Disease Neurons mainly affected Neurotrophic factors to which cell may respond 

Peripheral neuropathies Amyotrophic lateral sclerosis Alzheimer s disease Parkinson s disease Huntington s disease Sensory/motor neurons Spinal motor neurons Forebrain cholinergic neurons Nigral dopamine neurons Striatal GABA neurons NGF, IGF-1, NT-3, CNTF BDNF, IGF-1, CNTF, GDNF, NT-4/5 NGF, BDNF, NT-4/5 GDNF, BDNF, NT-3, NT-4/5 BDNF, NT-4/5 

Loss of cholinergic neurons of the basal forebrain is a characteristic feature of Alzheimer s disease. These neurons enervate the hippocampus (the brain s memory centre). They respond to NGF, BDNF and NT-4/5, e.g. NGF can rescue such cells in rodents after damage induced by cutting their axons. 

Degeneration of these same neurons is also associated with an age-dependent decrease in learning and memory ability. Infusion of NGF and NT-4/5 to aged rats appears to improve their spatial memory ability. Further studies in rodents have shown that physical exercise increased BDNF expression, which may explain why exercise is often a predictor of high mental function during ageing. 

---