We characterised the voltage-gated Ca²⁺ channels (VGCCs) in human cardiac fibroblasts (HCFs) and myofibroblasts (HCMFs) and investigated the effects of nitric oxide (NO) on apoptosis and on these channels. Western blotting and immunofluorescence analyses show that α-smooth muscle actin (a myofibroblast marker) was markedly expressed in passage (P) 12-15 but not in P4 HCF cells, whereas calponin (a fibroblast marker) was expressed only in P4 cells. Ca_V 1.2 (L-type) and Ca_V 3.3 (T-type) of VGCCs were highly expressed in P12-15 cells, but only weak Ca_V 2.3 (R-type) expression was identified in P4 cells using reverse transcription-polymerase chain reaction analysis. S-Nitroso-N-acetylpenicillamine (SNAP, an NO donor) decreased cell viability of HCMFs in a dose-dependent manner and induced apoptotic changes, and nifedipine (an L-type Ca²⁺ channel blocker) prevented apoptosis as shown with immunofluorescence staining and flow cytometry. Whole-cell mode patch-clamp recordings demonstrate the presence of L-type Ca²⁺ (I_C_a,L ) and T-type Ca²⁺ (I_C_a,T ) currents in HCMFs. SNAP inhibited I_C_a,L of HCMFs, but pre-treatment with ODQ (a guanylate cyclase inhibitor) or KT5823 (a PKG inhibitor) prevented it. Pre-treating cells with KT5720 (a PKA inhibitor) or SQ22536 (an adenylate cyclase inhibitor) blocked SNAP-induced inhibition of I_C_a,L . 8-Bromo-cyclic GMP or 8-bromo-cyclic AMP also inhibited I_C_a,L . However, pre-treatment with N-ethylmaleimide (a thiol-alkylating reagent) did not block the SNAP effect, nor did DL-dithiothreitol (a reducing agent) reverse it. These data suggest that high concentrations of NO injure HCMFs and inhibit I_C_a,L through the PKG and PKA signalling pathways but not through the S-nitrosylation pathway.

#	Concept	H-Index	Publications	Citations
1	Medicine	2	2	28
2	Cell Biology	2	2	28
3	Engineering	1	1	10
4	Biochemistry	1	1	10
5	Biomedical Engineering	1	1	10

	Year	Citations

About

Top Concepts