Effect of unsaturated fatty acid on muscarinic current in guinea pig gastric antral circular myocytes

摘要

AIM: To investigate the effect of ectogenesis unsaturated fatty acid on carbachol-induced muscarinic current (I_(CCh)) and its mechanism. METHODS: Using the whole-cell patch-clamp technique, I_(CCh) was recorded in single smooth muscle 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 I_(CCh) to 46 %+-8 %, 23 %+-5 %, and 3.8 %+-0.9 % at 1, 3, and 5 μmol/L. Another unsaturated fatty acid, linoleic acid (LA) also inhibited I_(CCh) in a dose-dependant manner. LA inhibited I_(CCh) to 69 %+-10 %, 35 %+-5 %, and 7.4 %+-1.2 % at 1, 5, and 10 μmol/L, respectively. The same concentration (5 μmol/L) of AA, LA, and oleic acid (OA) suppressed I_(CCh) to 3.8 %+-0.9 %, 35 %+-5 %, and 67 %+-9 %, respectively. The inhibitory potency sequence of these unsaturated fatty acids was AA>LA>OA. After 10-15 min of pretreatment with H-7 (a protein phosphorylation C inhibitor) 100 μmol/L or indomethacin (a cyclooxygenase inhibitor) 10 μmol/L, I_(CCh) 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 I_(CCh), and the inhibitory potency was related to the number of double bonds in fatty acid chain.