Effects of phospholipase A2 inhibitors on Ca2+ oscillations in pancreatic acinar cells.
High-affinity cholecystokinin (CCK) receptors were reported to be coupled with phospholipase A2 (PLA2)-arachidonic acid (AA) pathways to mediate Ca2+ oscillations and amylase secretion in rat pancreatic acinar cells. To investigate which types of PLA2 were involved in PLA2-AA pathways, the effects of specific inhibitors for type II and type IV PLA2 on Ca2+ oscillations and amylase secretion were studied in isolated rat pancreatic acini. An inhibitor of type IV (cytosolic) PLA2, AACOCF3 inhibited Ca2+ oscillations elicited by CCK-8 (30 pM) and JMV-180 (100 nM). AACOCF3 inhibited amylase secretion stimulated by JMV-180 and low concentrations of CCK-8 (< or =30 pM). On the other hand, an inhibitor of type II (secretory, nonpancreatic) PLA2 had no effects on Ca2+ oscillations and amylase secretion stimulated by CCK-8 and JMV-180. These results suggest that high-affinity CCK receptors are coupled to cytosolic PLA2 to mediate Ca2+ oscillations and amylase secretion in rat pancreatic acinar cells.
Mizuno
N
N
Department of Internal Medicine II, Nagoya University School of Medicine, Japan.
Naruse
S
S
Kitagawa
M
M
Ishiguro
H
H
Hayakawa
T
T
D000681:Amylases / Q000378:metabolism*; D000818:Animals; D016718:Arachidonic Acid / Q000502:physiology; D001095:Arachidonic Acids / Q000494:pharmacology*; D020013:Calcium Signaling / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D008297:Male; D010179:Pancreas / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D051381:Rats; D017208:Rats, Wistar; D011949:Receptors, Cholecystokinin / Q000187:drug effects* / Q000502:physiology; D012844:Sincalide / Q000031:analogs & derivatives* / Q000494:pharmacology*
D001095:Arachidonic Acids; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D011949:Receptors, Cholecystokinin; C081565:arachidonyltrifluoromethane; C058451:JMV 180; D016718:Arachidonic Acid; D010741:Phospholipases A; D054467:Phospholipases A2; D000681:Amylases; D012844:Sincalide