Effects of calmodulin inhibitors on amylase secretion from rat pancreatic acini.
To investigate the role of calmodulin in stimulus-secretion coupling in pancreatic acinar cells, we studied the effects of W-7, a calmodulin inhibitor, and KN-62, a specific inhibitor of Ca2+/calmodulin-dependent protein kinase II (Ca2+/CaM kinase II), on amylase secretion from rat pancreatic acini. Calmodulin inhibitor (W-7, 100 microM) and Ca2+/CaM kinase II inhibitor (KN-62, 10 microM) reduced amylase secretion stimulated by cholecystokinin (CCK) or carbachol. W-7 and KN-62 also inhibited amylase secretion stimulated by both calcium ionophore (A23187) and phorbol ester (12-O-tetradecanoylphorbol-13-acetate, TPA). To clarify the role of calmodulin in the interaction of intracellular mediators, pancreatic acini were permeabilized with streptolysin O. Following permeabilization, amylase secretion was stimulated by submicromolar free Ca2+, and this Ca(2+)-dependent amylase secretion was enhanced by guanosine 5'-[gamma-thio]triphosphate (GTP gamma S), TPA or cyclic adenosine 3',5'-monophosphate (cAMP). W-7 and KN-62 had no effects on amylase secretion stimulated by Ca2+ alone, but inhibited the enhancement in Ca(2+)-dependent amylase secretion by GTP gamma S, TPA or cAMP. These data suggest that calmodulin plays an important role in Ca(2+)-dependent amylase secretion from pancreatic acinar cells and in the interaction between Ca2+ and other intracellular messengers.
Ishiguro
H
H
Second Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Hayakawa
T
T
Kondo
T
T
Shibata
T
T
Kitagawa
M
M
Sakai
Y
Y
Sobajima
H
H
Nakae
Y
Y
Tanikawa
M
M
Hidaka
H
H
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives*; D000681:Amylases / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000502:physiology; D002147:Calmodulin / Q000037:antagonists & inhibitors* / Q000502:physiology*; D007546:Isoquinolines / Q000494:pharmacology*; D008297:Male; D010179:Pancreas / Q000187:drug effects / Q000201:enzymology*; D010879:Piperazines / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors; D051381:Rats; D015290:Second Messenger Systems / Q000502:physiology; D013449:Sulfonamides / Q000494:pharmacology*
D002147:Calmodulin; D007546:Isoquinolines; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D013449:Sulfonamides; C063302:KN 62; C017967:W 7; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000681:Amylases; D002118:Calcium