Magnesium lithospermate B decreases [Ca(2+)]i in endothelial cells by inhibiting K(+) currents.
Magnesium lithospermate B (MLB) is a hydrophilic active component of Salviae miltiorrhizae Radix. Studies have shown that MLB affected intracellular calcium ([Ca(2+)]i), but the underlying mechanism was unclear yet. The present work was aimed to investigate the underlying mechanism of MLB affecting [Ca(2+)]i in endothelial cells (ECs). Isolated mesentery arteries were employed to test the involvement of L-Ca(2+) channel. [Ca(2+)]i was measured in ECs loaded with Fluo-3. Membrane potential and membrane currents were recorded in ECs using patch-clamp techniques. Results showed that MLB did not inhibit Ca(2+) influx via L-Ca(2+) channel in isolated mesenteric arteries. However, MLB decreased [Ca(2+)]i in a concentration-dependent manner in ECs. MLB depolarized the membrane potential of ECs and inhibited K(+) currents. These results demonstrated that MLB decreased [Ca(2+)]i by inhibiting K(+) currents and depolarizing membrane potential in ECs.
Zhang
Haifei
H
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
Zhang
Jie
J
Zha
Ruopeng
R
Hu
Miaomiao
M
Wang
Yiping
Y
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004365:Drugs, Chinese Herbal; C061091:lithospermate B; D011188:Potassium; D002118:Calcium