Effect of unsaturated fatty acid on muscarinic current in guinea pig gastric antral circular myocytes.
OBJECTIVE
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 smooth muscle cell isolated from the antral circular smooth muscles 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 % at 1, 3, and 5 micromol/L. Another unsaturated fatty acid, linoleic acid (LA) also inhibited ICCh in a dose-dependant manner. LA inhibited ICCh to 69 %+/-10 %, 35 %+/-5 %, and 7.4 %+/-1.2 % at 1, 5, and 10 micromol/L, respectively. The same concentration (5 micromol/L) of AA, LA, and oleic acid (OA) suppressed ICCh 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 micromol/L or indomethacin (a cyclooxygenase inhibitor) 10 micromol/L, ICCh was inhibited by 5 micromol/L of AA to 5.5 %+/-0.7 % and 3.0 %+/-1.0 %, respectively.


CONCLUSIONS
The unsaturated fatty acids directly inhibited ICCh, and the inhibitory potency was related to the number of double bonds in fatty acid chain.
Cui
Yi-Feng
YF
Department of Physiology, Yanbian University College of Medicine, Yanji 133000, China.
Jin
Hai
H
Guo
Hui-Shu
HS
Li
Lin
L
Yu
Yong-Chun
YC
Xu
Wen-Xie
WX
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology*; D002469:Cell Separation; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D007213:Indomethacin / Q000494:pharmacology; D019787:Linoleic Acid / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000502:physiology*; D019301:Oleic Acid / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011706:Pyloric Antrum / Q000166:cytology / Q000502:physiology*
D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D016718:Arachidonic Acid; D019301:Oleic Acid; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D019787:Linoleic Acid; D007213:Indomethacin