不饱和脂肪酸对豚鼠胃窦环行肌细胞毒蕈碱电流的影响

摘要

目的:研究外源性不饱和脂肪酸对豚鼠胃窦平滑肌细胞毒蕈碱电流的影响及其作用机制.方法:利用膜片箝技术的全细胞记录法在急性分离的胃窦环行肌细胞上记录毒蕈碱电流.结果:在细胞外灌流液中给予花生四烯酸(arachidonic acid,AA)明显抑制ICCh,并具有量效关系;当AA的浓度在1,3和5 μmol/L时,分别抑制ICCh至46%±8%,23%±5%和3.8%±0.9%;另一种不饱和脂肪酸,亚麻酸(linoleic acid,LA)也抑制ICCh,在1,5和10μmol/L浓度分别抑制ICCh至69%±10%,35%±5%和7.4%±1.2%;相同浓度的三种不饱和脂肪酸(5 μmol/L)AA、LA和亚油酸(oleic acid,0A)分别抑制ICCh至3.8%±0.9%,35%±5%和67%±9%;用H-7(蛋白激酶C抑制剂)100 μmol/L或消炎痛(环氧化酶抑制剂)1 0 μmol/L预处理10-15分钟以后,AA分别抑制ICCh至5.5%±0.7%和3.0%±1.0%.结论:不饱和脂肪酸直接抑制毒蕈碱电流,且抑制程度与不饱和脂肪酸链中的双键数目有关.%AIM: To investigate the effect of ectogenesis unsaturated fatty acid on carbachol-induced muscarinic current (ICCh)and its mechanism. METHODS: Using the whole-cell patch-clamp technique, ICCh was recorded in single smoothmuscle cell isolated from the antral circular smooth mucles of guinea-pig stomach. RESULTS: Arachidonic acid(AA) was added in external perfusing solution and AA inhibited ICCh to 46 %±8 %, 23 %±5 %, and 3.8 %±0.9 % at1, 3, and 5 μmol/L. Another unsaturated fatty acid, linoleic acid (LA) also inhibited ICch in a dose-dependantmanner. LA inhibited ICCh to 69 %±10 %, 35 %±5 %, and 7.4 %±1.2 % at 1, 5, and 10 μmol/L, respectively. Thesame concentration (5 μmol/L) of AA, LA, and oleic acid (OA) suppressed IcCh to 3.8 %±0.9 %, 35 %±5 %, and67 %±9 %, respectively. The inhibitory potency sequence of these unsaturated fatty acids was AA＞LA＞OA. After10-15 min of pretreatment with H-7 (a protein phosphorylation C inhibitor) 100 μmol/L or indomethacin (acyclooxygenase inhibitor) 10 μmol/L, ICCh was inhibited by 5 μmol/L of AA to 5.5 %±0.7 % and 3.0 %±1.0 %,respectively. CONCLUSION: The unsaturated fatty acids directly inhibited ICCh, and the inhibitory potency wasrelated to the number of double bonds in fatty acid chain.