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Role of 100-kDa cytosolic PLA2 in ACh-induced contraction of cat esophageal circular muscle.
- Source :
-
The American journal of physiology [Am J Physiol] 1994 Sep; Vol. 267 (3 Pt 1), pp. G433-41. - Publication Year :
- 1994
-
Abstract
- We have shown that acetylcholine (ACh)-induced contraction of esophageal circular muscle cells is mediated by activation of protein kinase C (PKC). We now examine the role of phospholipase A2 (PLA2). ACh increases [3H]arachidonic acid release in esophageal but not in lower esophageal sphincter (LES) muscle. In addition, ACh-induced contraction of esophageal but not of LES cells was reduced by the PLA2 antagonist dimethyleicosadienoic acid and by antiserum to a 100-kDa cytosolic PLA2 (cPLA2). These data suggest that the 100-kDa cPLA2 plays a role in ACh-induced contraction of esophageal but not of LES muscle. In esophageal cells, arachidonic acid produced by PLA2 caused little contraction by itself but potentiated contraction induced by the PKC agonist diacylglycerol (DAG). The free fatty acids linoleic acid and linolenic acid also potentiated DAG-induced contraction. Indomethacin and nordihydroguaiaretic acid had no effect on arachidonic acid-induced potentiation of DAG. The potentiation of DAG-induced contraction by arachidonic acid was inhibited by the PKC inhibitor H-7, but it was not affected by the calmodulin inhibitor CGS-9343B. We conclude that a 100-kDa cPLA2 participates in ACh-induced esophageal contraction by producing arachidonic acid and potentiating DAG-induced activation of a PKC-dependent pathway.
- Subjects :
- Animals
Arachidonic Acid antagonists & inhibitors
Arachidonic Acid pharmacology
Cats
Diglycerides pharmacology
Drug Synergism
Esophagogastric Junction cytology
Esophagogastric Junction drug effects
Esophagogastric Junction physiology
Esophagus cytology
Esophagus physiology
Female
Male
Molecular Weight
Muscle, Smooth cytology
Muscle, Smooth physiology
Phospholipases A metabolism
Phospholipases A2
Precipitin Tests
Acetylcholine pharmacology
Cytosol enzymology
Esophagus drug effects
Muscle Contraction physiology
Muscle, Smooth drug effects
Phospholipases A physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0002-9513
- Volume :
- 267
- Issue :
- 3 Pt 1
- Database :
- MEDLINE
- Journal :
- The American journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 7943241
- Full Text :
- https://doi.org/10.1152/ajpgi.1994.267.3.G433