Effects of the Chinese herb component phellopterin on the increase in cytosolic free calcium in PC12 cells

✍ Scribed by Hai-Tao Li; Ling He; Jia-Bin Qiu

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 119 KB
• Volume: 68
• Category: Article
• ISSN: 0272-4391
• DOI: 10.1002/ddr.20169

✦ Synopsis

The present study investigated the effects of the Chinese Herb component, phellopterin on high K 1 and glutamate-induced extracellular calcium influx and caffeine or cyclopiazonic acid (CPA)-induced calcium release from internal stores in attached PC12 cells. Attached cells were loaded with the calcium fluorescent indicator Fluo-3/AM with the final concentration of 5 mM for 50 min at 371C and cytosolic free Ca 21 measured as fluorescent intensity (FI) (excitation: 488 nm; emission: 535 nm). When PC12 cells were exposed to extracellular Ca 21 ([Ca 21 ] 0 ) 2.0 mM, the FI for resting [Ca 21 ] i was 1,1887163, high K 1 (75 mM) and glutamate (10 mM) induced an increase in [Ca 21 ] i with peak values of 4,2707982 and 3,0967402, respectively. Phellopterin (0.1-100 mM) had no apparent effect on resting [Ca 21 ] i , but inhibited high K 1 and glutamate induced the increase in [Ca 21 ] i in a dose-dependent manner. When PC12 cells were exposed to Ca 21 -free solution, the FI for resting [Ca 21 ] i was 804777. Caffeine (40 mM) and CPA (30 mM) stimulated Ca 21 release from caffeine-ryanodine and inositol 1,4,5-tris-phosphate (InsP 3) -sensitive internal calcium stores, inducing an increase in [Ca 21 ] i to 2,9387362 and 1,8167291, respectively. Phellopterin (0.1-100 mmol/L) inhibited caffeine and CPA stimulated intracellular calcium release in a dose-dependent manner. In summary, phellopterin, a novel component isolated from Changii radix, inhibited Ca 21 influx induced by stimulation of voltage-gated and receptor-dependent calcium channels with a greater inhibition of receptor-dependent calcium channels. It also inhibited Ca 21 release from caffeine-ryanodine and InsP 3 -sensitive internal stores, being more potent for caffeine stimulation. Phellopterin may be a promising candidate for the development of new classes of calcium antagonists.