Differential regulation of the expression of nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3 after excitotoxicity in a ratmodel of Huntington's disease

In the present study we have evaluated changes in nerve growth factor (NGF) ,: brain-derived neurotrophic factor, and neurotrophin 3 (NT-3) mRNA expres sion induced by different glutamate receptor agonists injected into the neo striatum. Up-regulation of NGF expression was observed at 24 h after intras triatal quinolinate injection, an N-methyl-D-aspartate receptor agonist, an d this increase was maintained up to 7 days after lesion. NGF up-regulation was also apparent in alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) treatment from 6 to 16 h postinjection. Instead, BDNF was up-regulat ed only at 6 h after kainate or AMPA excitotoxicity. Interestingly, NT-3 mR NA was down-regulated from 10 to 16 h following AMPA lesion, while 1S,3R-1- aminocyclopentane-1,3-dicarboxylic acid injection enhanced NT-3 mRNA levels at 10 h. Our results show a specific neurotrophin response induced by stim ulation of each glutamate receptor. These activity-dependent changes might be involved in neuronal plasticity processes and may underlie the different ial vulnerability of striatal neurons observed in neurodegenerative disorde rs. (C) 1998 Academic Press.