TTX-sensitive Na+ and nifedipine-sensitive Ca2+ channels in rat vas deferens smooth muscle cells

The inward currents in single smooth muscle cells (SMC) isolated from epididymal part of rat vas deferens have been studied using whole-cell patch-clamp method. Depolarising steps from holding potential -90 mV evoked inward current with fast and slow components. the component with slow activation possessed voltage-dependent and pharmacological properties characteristic for Ca2+ current carried through L-type calcium channels (I-Ca). the fast component of inward current was activated at around -40 mV, reached its peak at 0 mV, and disappeared upon removal of Na ions from bath solution. This current was blocked in dose-dependent manner by tetrodotoxin (TTX) with an apparent dissociation constant of 6.7 nM. On the basis of voltage-dependent characteristics, TTX sensitivity of fast component of inward current and its disappearance in Na-free solution it is suggested that this current is TTX-sensitive depolarisation activated sodium current (I-Na) Cell dialysis with a pipette solution containing no macroergic compounds resulted in significant inhibition of I-Ca (depression of peak I-Ca by about 81% was observed by 13 min of dialysis), while I-Na remained unaffected during 50 min of dialysis. These data draw first evidence for the existence of TTX-sensitive Na+ current in single SMC isolated from rat vas deferens. These Na+ channels do not appear to be regulated by a phosphorylation process under resting conditions. (C) 1999 Elsevier Science B.V. All rights reserved.Natl Acad Sci Ukraine, Bogomoletz Inst Physiol, Nerve Muscle Physiol Dept, UA-24 Kiev, UkraineUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Pharmacol, São Paulo, BrazilWeb of Scienc

Mitochondrial involvement in carbachol-induced intracellular Ca2+ mobilization and contraction in rat gastric smooth muscle

Aims: Mitochondria are important modulators of Ca2+ homeostasis. However, it is not clear if they modulate and participate in smooth muscle signaling and contraction. the aim of the present work was to investigate the role of mitochondria in Ca2+ transients and contraction induced by metabotropic muscarinic receptor activation in rat gastric smooth muscle.Main methods: Carbachol (CC11)-induced contraction was investigated in the absence or presence of increasing concentration of mitochondrial protonophore, carbonyl cyanide p-(trifluoro-methoxy)phenyl-hydrazone (FCCP), in gastric fundus strips. Ca2+ and mitochondrial membrane potential (Delta Psi m) measurements were performed in primarily cultured gastric smooth muscle cells loaded with FURA-2 or TMRE dyes.Key findings: Results show that CCh (1 mu M)-induced contraction was inhibited by FCCP in a concentration-dependent manner. in cultured smooth muscle cells CCh (1 mu M) caused a cytosolic Ca2+ rise. Preincubation with FCCP strongly inhibited CCh-evoked Ca2+ transients indicating that mitochondria shape intracellular Ca2+ Signals. CCh induced elevations of Delta Psi m in 60% of the individual mitochondrion analyzed.Significance: Taken together our results indicate that CCh induces release of Ca2+ from intracellular stores, which may be modulated by mitochondria. Thus, mitochondria participate of the intracellular Ca2+ homeostasis in muscarinic contraction in gastric fundus smooth muscle. (C) 2011 Elsevier Inc. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fed Univ São Paulo UNIFESP EPM, Dept Pharmacol, Paulista Sch Med, São Paulo, BrazilFed Univ Pernambuco UFPE, Dept Pharmaceut Sci, Recife, PE, BrazilFed Univ São Paulo UNIFESP EPM, Dept Pharmacol, Paulista Sch Med, São Paulo, BrazilWeb of Scienc

Influência da remoção do íon Na+ sobre a atividade contrátil em ducto deferente de rato

BV UNIFESP: Teses e dissertaçõe

Autophagy as a Neuroprotective Mechanism Against 3-Nitropropionic Acid-Induced Murine Astrocyte Cell Death

Huntington's disease (HD) is a genetic neurodegenerative disorder that is characterized by severe striatal atrophy with extensive neuronal loss and gliosis. Although the molecular mechanism is not well understood, experimental studies use the irreversible mitochondrial inhibitor 3-nitropropionic acid (3-NP) to mimic the neuropathological features of HD. in this study, the role of autophagy as a neuroprotective mechanism against 3-NP-induced astrocyte cytotoxicity was evaluated. Autophagy is a catabolic process that is essential for the turnover of cytosolic proteins and organelles and is involved in the modulation of cell death and survival. We showed that 3-NP-induced apoptosis, which was accompanied by Bax and Beclin-1 upregulation, was dependent on acidic vesicular organelle (AVO) formation after a continuous exposure to 3-NP for 12 h. the upregulation of Bax and Beclin-1 as well as AVO formation were normalized 24 h after 3-NP exposure.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fed Univ São Paulo UNIFESP, Dept Pharmacol, BR-04044020 São Paulo, BrazilFed Univ São Paulo UNIFESP, Dept Pharmacol, BR-04044020 São Paulo, BrazilWeb of Scienc

AUTOPHAGY AND APOPTOSIS MODULATION IN OSTEOSARCOMA CELLS EXPOSED TO A NEW PALLADACYCLE COMPOUND

Univ Fed Sao Paulo UNIFESP, Dept Farmacol, Sao Paulo, BrazilUniv Fed Sao Paulo UNIFESP, Dept Biofis, Sao Paulo, BrazilUniv Bandeirante Sao Paulo, Sao Paulo, BrazilUniv Mogi das Cruzes, CIIB, Mogi Das Cruzes, SP, BrazilUniv Fed Sao Paulo UNIFESP, Dept Farmacol, Sao Paulo, BrazilUniv Fed Sao Paulo UNIFESP, Dept Biofis, Sao Paulo, BrazilWeb of Scienc

Autophagy inhibited Ehrlich ascitic tumor cells apoptosis induced by the nitrostyrene derivative compounds: Relationship with cytosolic calcium mobilization

Apoptosis induction is often associated with increased autophagy, indicating interplay between these two important cellular events in cell death and survival. in this study, the programmed cell death and autophagy induced by two nitrostyrene derivative compounds (NTS1 and NTS2) was studied using the tumorigenic Ehrlich ascitic tumor (EAT) cells. EAT cells were highly sensitive to NTS1 and NTS2 cytotoxicity in a dose-dependent manner. NTS1 and NTS2 IC50 was less than 15.0 mu M post 12 h incubation. Apoptosis was primarily induced by both compounds, as demonstrated by an increase in Annexin-V positive cells, concurrently with cytochrome c release from mitochondria to cytosol and caspase-3 activation. Although cytosolic Ca2+ mobilization is involved in autophagy as well as apoptosis in response to cellular stress in many cancer cell types, from the two nitrostyrene derivative compounds studied, mainly NTS1 mobilized this ion and disparate autophagy in EAT cells. These results suggest that EAT induced cell death by NTS1 and NTS2 involved a Ca2+-dependent and a Ca2+-independent pathways, respectively. in accordance with these results, the treatment of EAT cells with 3 methyladenine (3-MA), an autophagy inhibitor; significantly increased the number of apoptotic cells after NTS1 treatment, suggesting that pharmacological modulation of autophagy augments the NTS1 efficacy. Thus, we denote the importance of studies involving autophagy and apoptosis during pre-clinical studies of new drugs with anticancer properties. (C) 2011 Elsevier B. V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo UNIFESP, Escola Paulista Med, Dept Farmacol, São Paulo, BrazilUniv Estadual Campinas, UNICAMP, Dept Farmacol, FCM, Campinas, SP, BrazilUniversidade Federal de São Paulo UNIFESP, Escola Paulista Med, Dept Biofis, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Escola Paulista Med, Dept Farmacol, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Escola Paulista Med, Dept Biofis, São Paulo, BrazilWeb of Scienc