A novel inhibition of martentoxin on neuronal BK channel subtype (α+β4) and functional modulation of

• 作 者: JianShi[1]PingZheng[2]YongHuaJi[3]HuiQiongHe[1]RongZhao[1]JinChen[1]YingChen[3]JuanYang[3]LeiZhong[3]JianWeiZhang[3]XueQinShu[3]
• 机 构: Graduate School of the Chinese Academy of Sciences, Institute of Physiology, Shanghai Institutes for
• 出 处: The First Chinese International Bioactive Neuropeptide Confe
• 发表日期: 2007年期

　　Martentoxin as a 37 residues peptidyl toxin was capable of blocking large-conductance Ca2+-activated K+ (BK) channels in adrenal medulla chromaffin cells.The present study investigated the pharmacological discrimination of martentoxin on BK channels subtypes and implicated the physiological function of neuronal BK channels (c+β4).The results showed that the iberiotoxin-insensitive BK channels (α+β4) could be potemly blocked by martentoxin (IC50 =~80nM).In contrast,the iberiotoxin-sensitive BK channel (only α) showed a low sensitivity to martentoxin.The inhibitory effect of martentoxin on BK channels (α+β4) appears with a novel interaction mode,including Ca2+ dependence and two possible interaction sites:one for trapping and the other for inhibition.Furthermore,in vivo experimems also suggested that the inhibition of BK channels (α+β4) by martentoxin would induce exacerbated abno-mal discharges,which indicated a braking role of BK channels (α+β4) in spontaneous bursting activity.