Murthy K S, Makhlouf G M
Department of Physiology, Medical College of Virginia, Richmond 23298-0711.
Am J Physiol. 1995 Jan;268(1 Pt 1):C171-80. doi: 10.1152/ajpcell.1995.268.1.C171.
The signaling pathways mediating relaxation by vasoactive intestinal peptide (VIP), peptide histidine-isoleucine amide (PHI), isoproterenol (ISO), and sodium nitroprusside (SNP) were examined in dispersed rabbit and guinea pig gastric muscle cells. In rabbit muscle cells, SNP stimulated only guanosine 3',5'-cyclic monophosphate (cGMP) and cGMP-dependent protein kinase (cG-kinase) activity; VIP stimulated adenosine 3',5'-cyclic monophosphate (cAMP) and cGMP, and both cG-kinase and cAMP-dependent protein kinase (cA-kinase) activities; PHI and ISO stimulated only cAMP and cA-kinase activity, and at higher concentrations, cross-activated cG-kinase. All four agents elicited concentration-dependent relaxation. N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89; 1 microM) selectively inhibited cA-kinase activity and abolished relaxation when only cA-kinase was elevated. 8R,9S, 11S-(-)-9-methoxy-carbamyl-8-methyl-2,3,9,10-tetrahydro-8,11-epoxy- 1H,8H,11H-2,7b,11a-trizadibenzo-(a,g)-cy-cloocta-(c,d,e)- trinden-1-one (KT-5823; 1 microM) selectively inhibited cG-kinase activity and abolished relaxation when only cG-kinase was elevated. When both kinases were elevated, H-89 and KT-5823 partially inhibited relaxation and abolished relaxation in combination. In permeabilized guinea pig and rabbit muscle cells, all agents elicited relaxation and inhibited inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release. Both functions were inhibited in parallel fashion by protein kinase inhibitor PKI(6-22) and by KT-5823. We conclude that cA-kinase and cG-kinase act separately and in concert to inhibit IP3-dependent Ca2+ release and induce relaxation.
在分离的兔和豚鼠胃肌细胞中，研究了血管活性肠肽（VIP）、肽组氨酸异亮氨酸酰胺（PHI）、异丙肾上腺素（ISO）和硝普钠（SNP）介导舒张的信号通路。在兔肌细胞中，SNP仅刺激鸟苷3',5'-环磷酸（cGMP）和cGMP依赖性蛋白激酶（cG激酶）活性；VIP刺激腺苷3',5'-环磷酸（cAMP）和cGMP，以及cG激酶和cAMP依赖性蛋白激酶（cA激酶）活性；PHI和ISO仅刺激cAMP和cA激酶活性，且在较高浓度时交叉激活cG激酶。所有四种药物均引起浓度依赖性舒张。N-[2-(对溴肉桂氨基)乙基]-5-异喹啉磺酰胺（H-89；1微摩尔）选择性抑制cA激酶活性，并在仅cA激酶升高时消除舒张。8R,9S,11S-(-)-9-甲氧基甲酰基-8-甲基-2,3,9,10-四氢-8,11-环氧-1H,8H,11H-2,7b,11a-三氮杂二苯并-(a,g)-环辛-(c,d,e)-三茚-1-酮（KT-5823；1微摩尔）选择性抑制cG激酶活性，并在仅cG激酶升高时消除舒张。当两种激酶均升高时，H-89和KT-5823部分抑制舒张，并联合使用时消除舒张。在通透的豚鼠和兔肌细胞中，所有药物均引起舒张并抑制肌醇1,4,5-三磷酸（IP3）诱导的Ca2+释放。蛋白激酶抑制剂PKI(6-22)和KT-5823以平行方式抑制这两种功能。我们得出结论，cA激酶和cG激酶分别且协同作用以抑制IP3依赖性Ca2+释放并诱导舒张。
