Vitamin B2 inhibits glutamate release from rat cerebrocortical nerve terminals.
We examined the effect of riboflavin, vitamin B2, on the release of endogenous glutamate from nerve terminals purified from rat cerebral cortex. The release of glutamate evoked by 4-aminopyridine was inhibited by riboflavin. Further experiments indicated that riboflavin-mediated inhibition of glutamate release (i) results from a reduction of vesicular exocytosis, not from an inhibition of nonvesicular release; (ii) is associated with a decrease in presynaptic N-type and P/Q-type voltage-dependent Ca channel activity. These findings are the first to suggest that, in rat cerebrocortical nerve terminals, riboflavin suppresses voltage-dependent Ca channel activity and in so doing inhibits evoked glutamate release. This finding may explain the neuroprotective effects of vitamin B2 against neurotoxicity.
Wang
Su-Jane
SJ
School of Medicine bDepartment of Nutritional Science, Fu Jen Catholic University, Hsin-Chuang, Taipei Hsien, Taiwan.
Wu
Wen-Mein
WM
Yang
Feili-Lo
FL
Hsu
Guoo-Shyng Wang
GS
Huang
Chia-Yu
CY
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020865:Calcium Channels, P-Type / Q000502:physiology; D020907:Calcium Channels, Q-Type / Q000502:physiology; D020013:Calcium Signaling / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism; D005089:Exocytosis / Q000187:drug effects; D005470:Fluorometry; D018698:Glutamic Acid / Q000378:metabolism*; D008297:Male; D009411:Nerve Endings / Q000187:drug effects* / Q000378:metabolism; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012256:Riboflavin / Q000494:pharmacology*; D013570:Synaptic Membranes / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism; D050496:Vesicular Glutamate Transport Proteins / Q000378:metabolism; D014803:Vitamin B Complex / Q000494:pharmacology; D020960:omega-Conotoxins / Q000494:pharmacology
D002121:Calcium Channel Blockers; D020865:Calcium Channels, P-Type; D020907:Calcium Channels, Q-Type; D050496:Vesicular Glutamate Transport Proteins; D020960:omega-Conotoxins; D014803:Vitamin B Complex; D018698:Glutamic Acid; D015761:4-Aminopyridine; D002118:Calcium; D012256:Riboflavin