Inhibitory effect of C-type natriuretic peptide on L-type calcium channel currents in gastric antral myocytes of guinea pigs

Rok, strany: 2006, 365 - 377

The role of C-type natriuretic peptide (CNP) in the gastrointestinal tract is still unclear. This study was designed to investigate the effect of CNP on barium current (IBa) through the L-type calcium channel in gastric antral myocytes of guinea pigs. The whole-cell patch clamp technique was performed in gastric antral myocytes isolated by collagenase in guinea pigs. CNP significantly inhibited IBa in a dose-dependent manner at the concentrations of 0.001, 0.01, and 0.1 µmol/l, CNP inhibited IBa to 81.56 ± 2.48 %, 73.64 ± 3.65 %, and 57.77 ± 4.93 % of control at 0 mV, respectively. The values of steady-state half-inactivation voltage (33.6 ± 2.6 mV and 33.8 ± 3.4 mV, in control and CNP groups, respectively) or the half-activation voltage (−12.6 ± 2.2 mV and 12.4 ± 1.8 mV) of IBa were not significantly changed (p > 0.05, n = 6). 8-br-cGMP (1 mmol/l) mimicked the effect of CNP on IBa, and the peak current of IBa was inhibited from −403.84 ± 61.87 pA to 318.94 ± 67.17 pA (p < 0.05, n = 5). In the presence of LY83583 (0.1 µmol/l), a nonspecific inhibitor of guanylate cyclase, CNP (0.1 µmol/l)-induced inhibition of IBa was partially blocked (n = 13, p < 0.05 ). However, when the cell was pretreated with zaprinast (0.1 µmol/l), an inhibitor of cyclic guanosine monophosphate (cGMP) sensitive phosphoesterase, the inhibitory effect of CNP on IBa was significantly potentiated (n = 11, p < 0.05). KT5823 (1 µmol/l), a cGMP-dependent protein kinase (PKG) inhibitor, almost completely blocked CNP-induced inhibition of IBa. The results suggested that CNP can inhibit L-type calcium channel currents, and the inhibitory effect is mediated by pGC-cGMP-PKG-dependent signal pathway in gastric antral myocytes of guinea pigs.

ISO 690:

Sun, J., Huang, X., Xu, H., Li, X., Gao, L., Kim, Y., Xu, W. 2006. Inhibitory effect of C-type natriuretic peptide on L-type calcium channel currents in gastric antral myocytes of guinea pigs. In General Physiology and Biophysics, vol. 25, no.4, pp. 365-377. 0231-5882.

APA:

Sun, J., Huang, X., Xu, H., Li, X., Gao, L., Kim, Y., Xu, W. (2006). Inhibitory effect of C-type natriuretic peptide on L-type calcium channel currents in gastric antral myocytes of guinea pigs. General Physiology and Biophysics, 25(4), 365-377. 0231-5882.