Plant-derived amino acids increase hippocampal BDNF, NGF, c-fos and hsp70 mRNAs

Early alterations in mRNAs encoding neurotrophins and stress proteins were investigated following intracerebroventricular injections of beta-N-oxalylamino-L-alanine (BOAA) and beta-N-methylamino-L-alanine (BMAA) in adult rats using in situ hybridization. Major increases in heat-shock protein 70, c-fos and brain-derived neurotrophic factor (BDNF) mRNAs were seen in hippocampus 1 h after BOAA or BMAA injections. Nerve growth factor mRNA was profoundly increased in the dentate gyrus (DG) after both treatments. Four hours after BMAA injections increased hybridization to BDNF mRNA was still seen in hippocampus, in parallel with reduced neurotrophin-3 expression in the DG. These alterations are in accordance with previous findings of BOAA and BMAA as potent glutamate receptor agonists.