Regulation of glutamate level in rat brain through activation of glutamate dehydrogenase by Corydalis ternata.
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 (nerve- specific 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.
Lee
Kwan Ho
KH
Pulmonary Division of Internal Medicine, Yeungnam University School of Medicine, Daegu 707-717, Korea.
Huh
Jae-Wan
JW
Choi
Myung-Min
MM
Yoon
Seung Yong
SY
Yang
Seung-Ju
SJ
Hong
Hea Nam
HN
Cho
Sung-Woo
SW
D000818:Animals; D053119:Benzophenanthridines; D001600:Berberine Alkaloids / Q000494:pharmacology; D001921:Brain / Q000187:drug effects* / Q000201:enzymology; D031311:Corydalis / Q000737:chemistry*; D004789:Enzyme Activation / Q000187:drug effects; D005969:Glutamate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D051381:Rats
D053119:Benzophenanthridines; D001600:Berberine Alkaloids; D007527:Isoenzymes; D010936:Plant Extracts; D012333:RNA, Messenger; D018698:Glutamic Acid; D005969:Glutamate Dehydrogenase; C009093:protopine