The involvement of phospholipase A(2) in ethanol-induced gastric muscle contraction.
To understand the underlying mechanism of ethanol in tonic contraction, the effect of ethanol on phospholipase A(2) and phospholipase C activities and the effects of phospholipase inhibitors on ethanol-induced contraction of cat gastric smooth muscle were tested. Circular muscle strips (2.0 x 0.2 cm) obtained from the fundus of cat stomach were used to measure isometric contraction. Ethanol elicited tonic contraction and activated phospholipase A(2) activity in a dose-dependent manner. Phospholipase A(2) inhibitors, manoalide (0.1--10 microM) and oleyloxyethyl phosphorylcholine (1--10 microM), significantly inhibited ethanol-induced contraction. Furthermore, 342 mM ethanol-induced contraction was significantly inhibited by cyclooxygenase inhibitors, ibuprofen (10--100 microM) and indomethacin (10--100 microM), but not by lipoxygenase inhibitors. On the other hand, phospholipase C inhibitors had no effect on ethanol-induced contraction, indicating that phospholipase C is not involved in ethanol-induced contraction. It is suggested from the above results that ethanol-induced contraction in cat gastric smooth muscle is, in part, mediated by phospholipase A(2) and cyclooxygenase pathways.
Department of Pathophysiology, College of Pharmacy, Chung-Ang University, 221 Huksuk-dong, Dongjak-gu, Seoul 156-756, South Korea.
S S
SS
Sim
J C
JC
Choi
D S
DS
Min
D J
DJ
Rhie
S H
SH
Yoon
S J
SJ
Hahn
C J
CJ
Kim
M S
MS
Kim
Y H
YH
Jo
D000818:Animals; D002415:Cats; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D005748:Gastric Fundus / Q000187:drug effects* / Q000378:metabolism; D007052:Ibuprofen / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010741:Phospholipases A / Q000187:drug effects* / Q000378:metabolism; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013729:Terpenes / Q000494:pharmacology
D002492:Central Nervous System Depressants; D016861:Cyclooxygenase Inhibitors; D007295:Inositol Phosphates; D010726:Phosphodiesterase Inhibitors; D013729:Terpenes; D010767:Phosphorylcholine; D000431:Ethanol; C068170:oleyloxyethylphosphorylcholine; C045673:manoalide; D010741:Phospholipases A; D007052:Ibuprofen; D007213:Indomethacin