Effects of methylflavonolamine on free intracellular calcium in isolated embryonic rat brain cells.
OBJECTIVE
To observe the effects of methylflavonolamine (MFA) on free intracellular calcium concentration ([Ca2+]i) of isolated embryonic rat brain cells in presence and absence of high extracellular potassium and L-glutamate.


METHODS
[Ca2+]i was measured in a spectrofluorophotometer by preloading the cells with calcium sensitive fluorescent indicator Fura 2-AM.


RESULTS
Resting [Ca2+]i was 197 +/- 20 nmol.L-1 (n = 44) in the presence of Ca2+ 1.3 mmol.L-1 in Hanks' solution. MFA 0.15 mmol.L-1 had no effect on the resting [Ca2+]i. When extracellular Ca2+ was 1.3 mmol.L-1, MFA (0.03-0.3 mmol.L-1) concentration-dependently inhibited the [Ca2+]i elevation induced by high extracellular potassium, with an IC50 value of 0.14 (95% confidence limits: 0.05-0.42) mmol.L-1. At higher concentration (0.15-0.30 mmol.L-1), MFA decreased L-glutamate-induced [Ca2+]i elevation, with an IC50 of 0.20 (95% confidence limits: 0.01-3.40) mmol.L-1.


CONCLUSIONS
MFA inhibited Ca2+ influx through voltage-dependent calcium channel and, at higher concentration, through receptor-operated calcium channel in the embryonic rat brain cells.
Duan
W Z
WZ
Department of Pharmacology, Shanxi Medical College, Taiyuan, China.
Tang
Y Z
YZ
D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D005419:Flavonoids / Q000494:pharmacology*; D044948:Flavonols; D011189:Potassium Chloride / Q000037:antagonists & inhibitors; D051381:Rats
D002121:Calcium Channel Blockers; D005419:Flavonoids; D044948:Flavonols; C052073:SIPI 549; D011189:Potassium Chloride; D002118:Calcium