Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Biol Direct ; 18(1): 70, 2023 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-37899484

RESUMO

BACKGROUND: The study aimed to identify transcripts of specific ion channels in rat ventricular cardiomyocytes and determine their potential role in the regulation of ionic currents in response to mechanical stimulation. The gene expression levels of various ion channels in freshly isolated rat ventricular cardiomyocytes were investigated using the RNA-seq technique. We also measured changes in current through CaV1.2 channels under cell stretching using the whole-cell patch-clamp method. RESULTS: Among channels that showed mechanosensitivity, significant amounts of TRPM7, TRPC1, and TRPM4 transcripts were found. We suppose that the recorded L-type Ca2+ current is probably expressed through CaV1.2. Furthermore, stretching cells by 6, 8, and 10 µm, which increases ISAC through the TRPM7, TRPC1, and TRPM4 channels, also decreased ICa,L through the CaV1.2 channels in K+ in/K+ out, Cs+ in/K+ out, K+ in/Cs+ out, and Cs+ in/Cs+ out solutions. The application of a nonspecific ISAC blocker, Gd3+, during cell stretching eliminated ISAC through nonselective cation channels and ICa,L through CaV1.2 channels. Since the response to Gd3+ was maintained in Cs+ in/Cs+ out solutions, we suggest that voltage-gated CaV1.2 channels in the ventricular myocytes of adult rats also exhibit mechanosensitive properties. CONCLUSIONS: Our findings suggest that TRPM7, TRPC1, and TRPM4 channels represent stretch-activated nonselective cation channels in rat ventricular myocytes. Probably the CaV1.2 channels in these cells exhibit mechanosensitive properties. Our results provide insight into the molecular mechanisms underlying stretch-induced responses in rat ventricular myocytes, which may have implications for understanding cardiac physiology and pathophysiology.


Assuntos
Miócitos Cardíacos , Canais de Cátion TRPM , Ratos , Animais , Miócitos Cardíacos/metabolismo , Canais de Cátion TRPM/genética , Canais de Cátion TRPM/metabolismo , RNA , Ventrículos do Coração/metabolismo , Cátions/metabolismo , Cátions/farmacologia
2.
Physiol Rep ; 10(7): e15246, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35384354

RESUMO

The mechanoelectrical feedback (MEF) mechanism in the heart that plays a significant role in the occurrence of arrhythmias, involves cation flux through cation nonselective stretch-activated channels (SACs). It is well known that nitric oxide (NO) can act as a regulator of MEF. Here we addressed the possibility of SAC's regulation along NO-dependent and NO-independent pathways, as well as the possibility of S-nitrosylation of SACs. In freshly isolated rat ventricular cardiomyocytes, using the patch-clamp method in whole-cell configuration, inward nonselective stretch-activated cation current ISAC was recorded through SACs, which occurs during dosed cell stretching. NO donor SNAP, α1-subunit of sGC activator BAY41-2272, sGC blocker ODQ, PKG blocker KT5823, PKG activator 8Br-cGMP, and S-nitrosylation blocker ascorbic acid, were employed. We concluded that the physiological concentration of NO in the cell is a necessary condition for the functioning of SACs. An increase in NO due to SNAP in an unstretched cell causes the appearance of a Gd3+ -sensitive nonselective cation current, an analog of ISAC , while in a stretched cell it eliminates ISAC . The NO-independent pathway of sGC activation of α subunit, triggered by BAY41-2272, is also important for the regulation of SACs. Since S-nitrosylation inhibitor completely abolishes ISAC , this mechanism occurs. The application of BAY41-2272 cannot induce ISAC in a nonstretched cell; however, the addition of SNAP on its background activates SACs, rather due to S-nitrosylation. ODQ eliminates ISAC , but SNAP added on the background of stretch increases ISAC in addition to ODQ. This may be a result of the lack of NO as a result of inhibition of NOS by metabolically modified ODQ. KT5823 reduces PKG activity and reduces SACs phosphorylation, leading to an increase in ISAC . 8Br-cGMP reduces ISAC by activating PKG and its phosphorylation. These results demonstrate a significant contribution of S-nitrosylation to the regulation of SACs.


Assuntos
Miócitos Cardíacos , Óxido Nítrico , Animais , Sítios de Ligação , GMP Cíclico/metabolismo , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Guanilato Ciclase/metabolismo , Miócitos Cardíacos/metabolismo , Óxido Nítrico/metabolismo , Ratos
3.
J Physiol Biochem ; 75(1): 109-115, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30756238

RESUMO

The purpose of this study was to examine the effects of interferon-γ (IFN-γ) on calcium movement in rat ventricular myocytes. L-type Ca2+ currents (ICa,L) were recorded with the whole-cell configuration of the patch-clamp techniques. IFN-γ induces current density reduction at the test potential of 0 mV by 47.6 ± 7.4%. Heparin, a selective inhibitor of inositol-1,4,5-triphosphate (IP3)-induced Ca2+ release, applied via a patch pipette, induced an ICa,L amplitude decrease of about 46 ± 5.6%. The addition of IFN-γ to heparin-treated cells has no effect on ICa,L. Ryanodine induced an ICa,L current amplitude decrease of 35.1 ± 6.2%. The addition of IFN-γ to ryanodine-treated cells caused an additional ICa,L inhibiting of 17.6 ± 4.8%. Both cyclopiazonic acid (CPA), a specific SERCA inhibitor, and a combination of CPA and ryanodine caused a significant reduction of the ICa,L amplitudes. Subsequent addition of IFN-γ inhibited ICa,L for an additional 16.3 ± 4.4%. The employment of chelerythrine in this study prevented IFN-γ-induced L-type Ca2+ channel inhibition in only 10 min from the start of perfusion. Proposed mechanisms of regulation involved IFN-γ-induced IP3-sensitive Ca2+ release probably by a Ca2+-dependent translocation of PKC from the cytoplasm to the cell membrane as the obligatory first step of the IFN-γ-induced PKC-dependent L-type Ca2+ channel inhibition.


Assuntos
Canais de Cálcio Tipo L/metabolismo , Cálcio/metabolismo , Interferon gama/farmacologia , Miócitos Cardíacos/efeitos dos fármacos , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Transdução de Sinais/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Animais , Benzofenantridinas/farmacologia , Ventrículos do Coração/citologia , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Heparina/farmacologia , Indóis/farmacologia , Inositol 1,4,5-Trifosfato/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Técnicas de Patch-Clamp , Cultura Primária de Células , Proteína Quinase C/metabolismo , Transporte Proteico , Ratos , Ratos Wistar , Rianodina/farmacologia , Retículo Sarcoplasmático/efeitos dos fármacos , Retículo Sarcoplasmático/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA