Exp Mol Med.  2005 Aug;37(4):371-377.

Regulation of glutamate level in rat brain through activation of glutamate dehydrogenase by Corydalis ternata

• Lee KH
• Huh JW
• Choi MM
• Yoon SY
• Yang SJ
• Hong HN
• Cho SW

Abstract

When treated with protopine and alkalized extracts of the tuber of Corydalis ternata for one year, significant decrease in glutamate level and increase in glutamate dehydrogenase (GDH) activity was observed in rat brains. The expression of GDH between the two groups remained unchanged as determined by Western and Northern blot analysis, suggesting a post-translational regulation of GDH activity in alkalized extracts treated rat brains. The stimulatory effects of alkalized extracts and protopine on the GDH activity was further examined in vitro with two types of human GDH isozymes, hGDH1 (house-keeping GDH) and hGDH2 (nerve-specific GDH). Alkalized extracts and protopine activated the human GDH isozymes up to 4.8-fold. hGDH2 (nervespecific GDH) was more sensitively affected by 1 mM ADP than hGDH1 (house-keeping GDH) on the activation by alkalized extracts. Studies with cassette mutagenesis at ADP-binding site showed that hGDH2 was more sensitively regulated by ADP than hGDH1 on the activation by Corydalis ternata. Our results suggest that prolonged exposure to Corydalis ternata may be one of the ways to regulate glutamate concentration in brain through the activation of GDH.

Keyword

glutamate dehydrogenase; glutamates; plant extracts; plants, medicinal; protopine

MeSH Terms

Animals
Berberine Alkaloids/pharmacology
Brain/*drug effects/enzymology
Corydalis/*chemistry
Enzyme Activation/drug effects
Glutamate Dehydrogenase/genetics/*metabolism
Glutamic Acid/*metabolism
Isoenzymes/genetics/metabolism
Plant Extracts/pharmacology
RNA, Messenger/analysis/metabolism
Rats
Research Support, Non-U.S. Gov't