Okayama N, Joh T, Miyamoto T, Kato T, Itoh M
First Department of Internal Medicine, Nagoya City University Medical School, Japan.
Dig Dis Sci. 1994 Dec;39(12):2547-57. doi: 10.1007/BF02087689.
We evaluated the role of myosin light-chain kinase (MLCK) and protein kinase C (PKC) in pepsinogen secretion from guinea pig gastric chief cells using a monolayer culture system of chief cells and an enzyme immunoassay system for guinea pig pepsinogen. An MLCK inhibitor, 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine (ML-9), significantly inhibited both the basal pepsinogen secretion and the secretion by carbamylcholine chloride (carbachol) or ionomycin without affecting intracellular free Ca2+ concentration ([Ca2+]i), but not by 12-O-tetradecanoylphorbol-13- acetate (TPA) or forskolin. A PKC inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), significantly reduced the pepsinogen secretion by carbachol or TPA, but not by forskolin or ionomycin, and did not affect the basal secretion and the [Ca2+]i elevated by carbachol or ionomycin. We concluded that: (1) MLCK plays an important role in basal and drug-stimulated pepsinogen secretion, (2) MLCK is involved in the Ca(2+)-dependent intracellular pathway but not in the cyclic adenosine monophosphate (cAMP) dependent pathway, (3) PKC is irrelevant to activation of MLCK, and (4) increases in cAMP and [Ca2+]i are independent of activation of PKC.
我们使用豚鼠胃主细胞单层培养系统和豚鼠胃蛋白酶原酶免疫分析系统，评估了肌球蛋白轻链激酶（MLCK）和蛋白激酶C（PKC）在豚鼠胃主细胞胃蛋白酶原分泌中的作用。一种MLCK抑制剂，1-(5-氯萘-1-磺酰基)-1H-六氢-1,4-二氮杂卓（ML-9），显著抑制基础胃蛋白酶原分泌以及氯化氨甲酰胆碱（卡巴胆碱）或离子霉素刺激的分泌，且不影响细胞内游离钙离子浓度（[Ca2+]i），但对12-O-十四酰佛波醇-13-乙酸酯（TPA）或福斯高林刺激的分泌无抑制作用。一种PKC抑制剂，1-(5-异喹啉磺酰基)-2-甲基哌嗪（H-7），显著降低卡巴胆碱或TPA刺激的胃蛋白酶原分泌，但对福斯高林或离子霉素刺激的分泌无影响，且不影响基础分泌以及卡巴胆碱或离子霉素升高的[Ca2+]i。我们得出以下结论：（1）MLCK在基础和药物刺激的胃蛋白酶原分泌中起重要作用；（2）MLCK参与钙依赖的细胞内途径，但不参与环磷酸腺苷（cAMP）依赖的途径；（3）PKC与MLCK的激活无关；（4）cAMP和[Ca2+]i的升高与PKC的激活无关。
