Effect of dendroaspis natriuretic peptide (DNP) on L-type calcium channel current and its pathway.
Dendroaspis natriuretic peptide (DNP), a newly-described natriuretic peptide, relaxes gastrointestinal smooth muscle. L-type calcium channel currents play an important role in regulating smooth muscle contraction. The effect of DNP on L-type calcium channel currents in gastrointestinal tract is still unclear. This study was designed to investigate the effect of DNP on barium current (I(Ba)) through the L-type calcium channel in gastric antral myocytes of guinea pigs and cGMP-pathway mechanism. The whole-cell patch-clamp technique was used to record L-type calcium channel currents. The content of cGMP in guinea pig gastric antral smooth muscle and perfusion solution was measured using radioimmunoassay. DNP markedly enhanced cGMP levels in gastric antral smooth muscle tissue and in perfusion medium. DNP concentration-dependently inhibited I(Ba) in freshly isolated guinea pig gastric antral circular smooth muscle cells (SMCs) of guinea pigs. DNP-induced inhibition of I(Ba) was partially blocked by LY83583, an inhibitor of guanylate cyclase. KT5823, a cGMP-dependent protein kinase (PKG) inhibitor, almost completely blocked DNP-induced inhibition of I(Ba). However, DNP-induced inhibition of I(Ba) was potentiated by zaprinast, an inhibitor of cGMP-sensitive phosphodiesterase. Taken together, DNP inhibits L-type calcium channel currents via pGC-cGMP-PKG-dependent signal pathway in gastric antral myocytes of guinea pigs.
Zhang
Shu-Ying
SY
Department of Internal Medicine, Affiliated Zhongshan Hospital of Dalian University, Dalian 116001, China. zhangsy1868@yahoo.com.cn
Cai
Zheng-Xu
ZX
Li
Ping
P
Cai
Chun-Yu
CY
Qu
Cheng-Long
CL
Guo
Hui-Shu
HS
D000634:Aminoquinolines / Q000494:pharmacology; D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D002227:Carbazoles / Q000494:pharmacology; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D004546:Elapid Venoms / Q000494:pharmacology*; D004594:Electrophysiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D006168:Guinea Pigs; D036341:Intercellular Signaling Peptides and Proteins; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology*; D011688:Purinones / Q000494:pharmacology; D011706:Pyloric Antrum / Q000166:cytology*; D011863:Radioimmunoassay
D000634:Aminoquinolines; D020746:Calcium Channels, L-Type; D002227:Carbazoles; C075597:Dendroaspis natriuretic peptide; D004546:Elapid Venoms; D004791:Enzyme Inhibitors; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D011688:Purinones; C073601:KT 5823; C041715:6-anilino-5,8-quinolinedione; D017869:Cyclic GMP-Dependent Protein Kinases; D006162:Guanylate Cyclase; C011145:zaprinast; D006152:Cyclic GMP