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1.
J Geophys Res Space Phys ; 127(4): e2021JA030238, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35866072

RESUMO

Discrete aurora at Mars, characterized by their small spatial scale and tendency to form near strong crustal magnetic fields, are emissions produced by particle precipitation into the Martian upper atmosphere. Since 2014, Mars Atmosphere and Volatile EvolutioN's (MAVEN's) Imaging Ultraviolet Spectrograph (IUVS) has obtained a large collection of UV discrete aurora observations during its routine periapsis nightside limb scans. Initial analysis of these observations has shown that, near the strongest crustal magnetic fields in the southern hemisphere, the IUVS discrete aurora detection frequency is highly sensitive to the interplanetary magnetic field (IMF) clock angle. However, the role of other solar wind properties in controlling the discrete aurora detection frequency has not yet been determined. In this work, we use the IUVS discrete aurora observations, along with MAVEN observations of the upstream solar wind, to determine how the discrete aurora detection frequency varies with solar wind dynamic pressure, IMF strength, and IMF cone angle. We find that, outside of the strong crustal field region (SCFR) in the southern hemisphere, the aurora detection frequency is relatively insensitive to the IMF orientation, but significantly increases with solar wind dynamic pressure, and moderately increases with IMF strength. Interestingly however, although high solar wind dynamic pressures cause more aurora to form, they have little impact on the brightness of the auroral emissions. Alternatively, inside the SCFR, the detection frequency is only moderately dependent on the solar wind dynamic pressure, and is much more sensitive to the IMF clock and cone angles. In the SCFR, aurora are unlikely to occur when the IMF points near the radial or anti-radial directions when the cone angle (arccos(B x /|B|)) is less than 30° or between 120° and 150°. Together, these results provide the first comprehensive characterization of how upstream solar wind conditions affect the formation of discrete aurora at Mars.

2.
Oper Dent ; 42(1): 19-29, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28002695

RESUMO

The aim of this randomized controlled clinical trial was to compare the clinical effectiveness of different polishing systems and self-etch adhesives in class V composite resin restorations. A total of 164 noncarious cervical lesions (NCCLs) from 35 patients were randomly allocated to one of four experimental groups, each of which used a combination of polishing systems and adhesives. The two polishing systems used were Sof-Lex XT (Sof), a multistep abrasive disc, and Enhance/Pogo (EP), a simplified abrasive-impregnated rubber instrument. The adhesive systems were Clearfil SE bond (CS), a two-step self-etch adhesive, and Xeno V (XE), a one-step self-etch adhesive. All NCCLs were restored with light-cured microhybrid resin composites (Z250). Restorations were evaluated at baseline and at 6, 12, 18, and 24 months by two blinded independent examiners using modified FDI criteria. The Fisher exact test and generalized estimating equation analysis considering repeated measurements were performed to compare the outcomes between the polishing systems and adhesives. Three restorations were dislodged: two in CS/Sof and one in CS/EP. None of the restorations required any repair or retreatment except those showing retention loss. Sof was superior to EP with regard to surface luster, staining, and marginal adaptation (p<0.05). CS and XE did not show differences in any criteria (p>0.05). Sof is clinically superior to EP for polishing performance in class V composite resin restoration. XE demonstrates clinically equivalent bonding performance to CS.


Assuntos
Condicionamento Ácido do Dente/métodos , Resinas Compostas/química , Polimento Dentário/métodos , Restauração Dentária Permanente/métodos , Adulto , Idoso , Cimentos Dentários , Estética Dentária , Feminino , Humanos , Cura Luminosa de Adesivos Dentários , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Cimentos de Resina , Propriedades de Superfície
3.
Science ; 350(6261): aad0313, 2015 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-26542577

RESUMO

Planetary auroras reveal the complex interplay between an atmosphere and the surrounding plasma environment. We report the discovery of low-altitude, diffuse auroras spanning much of Mars' northern hemisphere, coincident with a solar energetic particle outburst. The Imaging Ultraviolet Spectrograph, a remote sensing instrument on the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, detected auroral emission in virtually all nightside observations for ~5 days, spanning nearly all geographic longitudes. Emission extended down to ~60 kilometer (km) altitude (1 microbar), deeper than confirmed at any other planet. Solar energetic particles were observed up to 200 kilo--electron volts; these particles are capable of penetrating down to the 60 km altitude. Given minimal magnetic fields over most of the planet, Mars is likely to exhibit auroras more globally than Earth.

4.
Arch Pharm Res ; 24(5): 390-6, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11693537

RESUMO

Synthesized 6-arylamino-5,8-quinolinediones 4a-4j and 6-chloro-7-arylamino-5,8-isoquinolinediones 5a-5g were evaluated for effects on NAD(P)H: quinone oxidoreductase (NQO1) activity with the cytosolic fractions derived from cultured human lung cancer cells and their cytotoxicity in cultured several human solid cancer cell lines. The 5,8-quinolinediones 4 and 5,8-isoquinolinediones 5 affected the reduction potential by NQO1 activity and showed a potent cytotoxic activity against human cancer cell lines. The tested compounds 4a, 5c, 5f, and 5g were considered as more potent cytotoxic agents. The compounds 4d, 5b, 5c, 5e and 5g were comparable modulators of NQO1 activity.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , NAD(P)H Desidrogenase (Quinona)/antagonistas & inibidores , Quinolonas/síntese química , Quinolonas/farmacologia , Quinonas/síntese química , Quinonas/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Humanos , Indicadores e Reagentes
5.
Bioorg Med Chem ; 9(11): 2979-86, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11597479

RESUMO

We report upon the synthesis of the following derivatives: N-substituted-pyridino[2,3-f]indole-4,9-dione, and 6-(alpha-diethoxycarbonyl-methyl)-7-substituted-amino-quinoline-5,8-dione, which contain the active quinoline-5,8-dione (VII) moiety. The cytotoxic activities of these compounds have been tested in SRB (SulfoRhodamine B) assays against the cancer cell lines of A-549 (human lung cancer), SK-MEL-2 (human melanoma cancer), SK-OV-3 (human ovarian cancer), XF-498 (human brain cancer) and HCT 15 (human colon cancer). The compound, N-benzyl-3-ethoxycarbonyl-2-hydroxy-pyridino[2,3-f]indole-4,9-dione (A-9), also showed higher activity than cis-platin. The highest level of cytotoxic activity in these human tumor cell lines was observed in the compound 6-(alpha-diethoxycarbonyl-methyl)-7-(2-methyl-phenylamino)-quinoline-5,8-dione (B-3).


Assuntos
Antineoplásicos/síntese química , Indóis/farmacologia , Quinolonas/farmacologia , Quinonas/farmacologia , Antineoplásicos/farmacologia , Divisão Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indóis/síntese química , Indóis/química , Concentração Inibidora 50 , Biossíntese de Proteínas , Proteínas/efeitos dos fármacos , Piridinas/síntese química , Piridinas/química , Piridinas/farmacologia , Quinolonas/síntese química , Quinolonas/química , Quinonas/síntese química , Quinonas/química , Relação Estrutura-Atividade , Células Tumorais Cultivadas/efeitos dos fármacos
6.
J Nat Prod ; 64(10): 1301-4, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11678655
7.
Arch Pharm Res ; 24(4): 276-80, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11534756

RESUMO

Substituted isoquinolin-1-ones (1) were synthesized to test their in vitro anticancer activity. 3-Biphenyl-N-methylisoquinolin-1-one (7) showed the most potent anticancer activity against five different human cancer cell lines.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Isoquinolinas/síntese química , Isoquinolinas/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indicadores e Reagentes , Espectroscopia de Ressonância Magnética , Relação Estrutura-Atividade , Células Tumorais Cultivadas
8.
J Nat Prod ; 64(8): 1059-63, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11520227

RESUMO

Ten new (1, 4-6, 9-14) and four known (2, 3, 7, 8) diacetylenes have been isolated from a brine shrimp active fraction of the methanolic extract of the stony coral Montipora sp. The structures were determined by combined spectroscopic methods. The compounds exhibited significant cytotoxicity against a small panel of human solid tumor cell lines. Montiporyne A (15), a previously reported congener, was also found to induce apoptosis in human colon tumor cell.


Assuntos
Acetileno/isolamento & purificação , Antineoplásicos/isolamento & purificação , Cnidários/química , Acetileno/análogos & derivados , Acetileno/química , Acetileno/farmacologia , Alcinos , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Neoplasias do Colo , Humanos , Coreia (Geográfico) , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Estereoisomerismo , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo , Difração de Raios X
9.
J Cardiovasc Pharmacol ; 38(1): 11-20, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11444494

RESUMO

Polychlorinated biphenyls (PCBs) have been known as serious environmental pollutants, causing developmental delays, motor dysfunction, and decrease in brain dopamine level in humans and animals. We have investigated the effects of a PCB congener, 2,2',6-trichlorobiphenyl (PCB 19) on contractile force, Ca2+ transient, and L-type Ca2+ current (I(Ca,L)) in guinea pig ventricular myocytes stimulated at a rate of 0.25-0.33 Hz. PCB 19 decreased contractile force in a concentration-dependent manner. During the negative inotropic response, the action potential duration at 20% (APD20), 90% of repolarization (APD90), and the action potential amplitude (APA) were decreased concentration dependently: 30 microM PCB 19 reduced APD20, APD90 and APA by 36.7 +/- 3.5%, 22.6 +/- 3.9%, and 2.4 +/- 0.6%, respectively (n = 11, p < 0.01). PCB 19 30 microM decreased the Ca2+ transient and the I(Ca,L) by 46.8 +/- 1.8% (n = 9, p < 0.01) and 47.1 +/- 3.1% (n = 9, p < 0.01), respectively. The results suggest that PCB 19 decreased the Ca2+ transient through inhibition of L-type Ca2+ channels and that the decreased Ca2+ transient consequently caused a negative inotropic effect in cardiac myocytes.


Assuntos
Canais de Cálcio Tipo L/fisiologia , Poluentes Ambientais/farmacologia , Contração Miocárdica/efeitos dos fármacos , Miocárdio/metabolismo , Animais , Cobaias , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Contração Miocárdica/fisiologia , Miocárdio/citologia , Bifenilos Policlorados/farmacologia
11.
Planta Med ; 67(4): 358-9, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11458455

RESUMO

Costunolide, a germacrane sesquiterpene lactone isolated from the stem bark of Magnolia sieboldii demonstrated a significant inhibition upon the farnesylation process of human lamin-B by farnesyl-proteintransferase (FPTase), in a dose dependent manner in vitro (IC50 value was calculated as 20 microM). It was also found to exhibit an inhibition upon the proliferation of cultured human tumor cells, i.e., A549 (non small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nerve system) and HCT-15 (colon), in vitro.


Assuntos
Alquil e Aril Transferases/antagonistas & inibidores , Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Medicamentos de Ervas Chinesas/química , Inibidores Enzimáticos/farmacologia , Plantas Medicinais/química , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Antineoplásicos Fitogênicos/química , Encéfalo/enzimologia , Humanos , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Brotos de Planta/química , Ratos , Sesquiterpenos/química
12.
J Nat Prod ; 64(4): 533-5, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11325244

RESUMO

A known (1) and four new (2--5) lyso-PAF (platelet activating factor) derivatives were isolated from the sponge Spirastrella abata. Two of them are unprecedented in having a methoxy group at C-2'. The structures have been determined by combined spectroscopic methods. Their inhibitory effect on the biosynthesis of cholesterol and cytotoxicity against human solid tumor cell lines are reported.


Assuntos
Fator de Ativação de Plaquetas/análogos & derivados , Fator de Ativação de Plaquetas/isolamento & purificação , Animais , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Fator de Ativação de Plaquetas/química , Poríferos
13.
J Nat Prod ; 64(12): 1565-7, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11754614

RESUMO

New polyacetylenic alcohols (1-5) have been isolated as cytotoxic principles from the marine sponge Petrosia sp. The compounds were particularly cytotoxic against a human melanoma cell line (SK-MEL-2). The gross structures were established on the basis of NMR and MS data, and the absolute configuration was determined by the modified Mosher's method.


Assuntos
Acetileno/análogos & derivados , Acetileno/isolamento & purificação , Álcoois/isolamento & purificação , Antineoplásicos/isolamento & purificação , Polímeros/isolamento & purificação , Poríferos/química , Acetileno/química , Acetileno/farmacologia , Álcoois/química , Álcoois/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Neoplasias do Sistema Nervoso Central , Cromatografia Líquida de Alta Pressão , Neoplasias do Colo , Replicação do DNA/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Coreia (Geográfico) , Neoplasias Pulmonares , Espectrometria de Massas , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Neoplasias Ovarianas , Polímeros/química , Polímeros/farmacologia , Poli-Inos , Vírus 40 dos Símios/efeitos dos fármacos , Neoplasias Cutâneas , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo , Células Tumorais Cultivadas/efeitos dos fármacos
14.
Anticancer Drugs ; 11(9): 715-25, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11129734

RESUMO

A new class of water-soluble cyclotriphosphazene-(diamine)platinum(II) conjugate drugs [NP(Am-Li2)(Am.PtA2)]3 (Am: dicarboxylic amino acid; A2: diamine) has been synthesized and characterized by means of elemental analysis, multinuclear (1H, 31P, 13C, 195Pt) NMR and IR spectroscopies. All the title compounds were subjected to both in vitro and in vivo assays against the murine leukemia L1210 cell line and selected human tumor cells. Most of the title compounds have shown higher in vivo antitumor activity than cisplatin and carboplatin, and, in particular, [NP(L-Glu-Li2)(L-Glu.Pt(-dach)]3 (Glu=glutamate, dach=trans(+/-)-1,2-diaminocyclohexane) showed extraordinary high activity (ILS>500%) equally against both parent and cisplatin-resistant leukemia L1210 cell lines. Furthermore, this candidate compound (KI 60606) exhibited a wider spectrum of in vitro activity by showing higher cytotoxicity against all the selected human tumor cells than cisplatin and, therefore, was subjected to preclinical studies which are now near completion.


Assuntos
Antineoplásicos/síntese química , Nitrilas/síntese química , Compostos Organoplatínicos/síntese química , Compostos de Fósforo/síntese química , Animais , Antineoplásicos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Leucemia L1210/tratamento farmacológico , Espectroscopia de Ressonância Magnética , Camundongos , Nitrilas/farmacologia , Compostos Organoplatínicos/farmacologia , Compostos de Fósforo/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacos
15.
Clin J Oncol Nurs ; 4(2): 67-71, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11107378

RESUMO

Gynecologic cancers will account for approximately 81,000 new cases of cancer this year. Although much is known about the risk factors for cervical, ovarian, and endometrial cancers, less is known about vaginal and vulvar cancer risk factors. Generally, risk factors and associations for gynecologic cancers are behavioral, reproductive, hormonal, and genetic related. Research continues to verify and refute the impact of certain factors. All nurses must be knowledgeable about the risk factors and associations for these cancers.


Assuntos
Neoplasias dos Genitais Femininos/epidemiologia , Neoplasias dos Genitais Femininos/etiologia , Feminino , Neoplasias dos Genitais Femininos/classificação , Neoplasias dos Genitais Femininos/patologia , Saúde Global , Humanos , Enfermagem Oncológica , Fatores de Risco , Estados Unidos/epidemiologia
16.
Clin J Oncol Nurs ; 4(2): 73-7, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11107379

RESUMO

Screening interventions for gynecologic cancers involve identifying risk factors and high-risk groups of women, counseling for risk factor reduction, and recommending early detection strategies. All nurses can conduct gynecologic risk assessments, and advanced practice nurses can perform physical exams. All women must be knowledgeable about risk factors because gynecologic cancers are curable when diagnosed in the early stages. Nursing interventions include developing culturally sensitive programs and educational materials for targeted populations and educating women in all groups to raise awareness about gynecologic cancer risks.


Assuntos
Neoplasias dos Genitais Femininos/diagnóstico , Neoplasias dos Genitais Femininos/etiologia , Programas de Rastreamento/métodos , Distribuição por Idade , Fatores Etários , Feminino , Neoplasias dos Genitais Femininos/epidemiologia , Neoplasias dos Genitais Femininos/enfermagem , Humanos , Anamnese/métodos , Enfermeiros Clínicos , Enfermagem Oncológica , Exame Físico/métodos , Medição de Risco , Fatores de Risco
17.
J Nat Prod ; 63(11): 1511-4, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11087594

RESUMO

Six new acetylenic compounds (1-6) with cytotoxic activities against human solid tumor cell lines (SK-OV-3, SK-MEL-2, XF498, and HCT15) have been isolated from the stony coral Montipora sp. Structures of the compounds 1-6 were elucidated based on analysis of the NMR and MS data.


Assuntos
Antineoplásicos/isolamento & purificação , Cnidários/química , Ácidos Graxos Insaturados/isolamento & purificação , Animais , Antineoplásicos/farmacologia , Artemia , Cromatografia Líquida de Alta Pressão , Ensaios de Seleção de Medicamentos Antitumorais , Ácidos Graxos Insaturados/farmacologia , Humanos , Coreia (Geográfico) , Espectroscopia de Ressonância Magnética
18.
J Cell Physiol ; 185(2): 200-6, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11025441

RESUMO

We investigated the expression of ryanodine receptors (RyRs) in cultured human melanocytes with immunocytochemistry and reverse transcriptase-polymerase chain reaction. With the use of a monoclonal antibody, RyR immunoreactivity was detected in the cytoplasm of melanocytes, and was further confirmed by RT-PCR assay. The PCR products were cut with restriction enzymes specific for each RyR isoform. Using the RyR1-specific restriction enzyme SacI yielded fragments of 300, 100, and 130 base pairs, consistent with the expression of RyR1 isoforms. The function of RyR in Ca(2+) signaling was investigated using single-cell fura-2 imaging. Ryanodine (1 to approximately 100 microM) induced significant elevation of cytoplasmic Ca(2+) in single human melanocytes in a dose-dependent manner. The ryanodine-induced [Ca(2+)](i) increase was inhibited by neomycin. Furthermore, ryanodine inhibited proliferation and stimulated pigmentation of human melanocytes. This study demonstrates that the RyR1 isoform is expressed in cultured human melanocytes, and suggests that the RyR may be involved in regulating the intracellular Ca(2+) responses involved in proliferation and pigmentation of cultured human melanocytes.


Assuntos
Melanócitos/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Cálcio/metabolismo , Divisão Celular/efeitos dos fármacos , Células Cultivadas , Citosol/metabolismo , Humanos , Melanócitos/fisiologia , Concentração Osmolar , Pigmentação/efeitos dos fármacos , Rianodina/farmacologia
19.
Bioorg Med Chem ; 8(8): 2079-83, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11003153

RESUMO

2-Methyl-1-substituted-imidazo[4,5-g]quinoline-4,9-diones and 7,8-dihydro-10H-[1,4]oxazino-[3',4':2,3]imidazo[4,5-g]quinoline-5, 12-dione (19) derivatives have been synthesized from 6,7-dichloro-5,8-quinolinedione for developing the new anticancer drugs. Our study on the cytotoxicity of imidazoquinolinedione derivatives has revealed that 7,8-dihydro-10H-[1,4]oxazino-[3',4':2,3]imidazo[4,5-g]quinoline-5, 12-dione (19), a tetracyclic heteroquinone analogue, exhibited high cytotoxicity on human colon tumor cell (HCT 15) in vitro SRB assay. The IC50 value of this compound was 0.026 microg/mL whereas those of doxorubicin and cisplatin were 0.023 microg/mL and 1.482 microg/mL, respectively. Meanwhile compounds 5-7 and 12 in the series of 1-substituted-imidazoquinolinediones showed relatively good activity on human brain tumor cell lines (XF 498).


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Imidazóis/síntese química , Imidazóis/farmacologia , Quinolinas/síntese química , Quinolinas/farmacologia , Antineoplásicos/química , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Imidazóis/química , Substâncias Intercalantes/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Quinolinas/química , Relação Estrutura-Atividade , Células Tumorais Cultivadas
20.
Am J Physiol Heart Circ Physiol ; 279(4): H1661-8, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11009453

RESUMO

We investigated the role of protein kinase C (PKC) in alpha(1)-adrenergic regulation of intracellular Na(+) activity (a(Na)(i)) in single guinea pig ventricular myocytes. a(Na)(i) and membrane potentials were measured with the Na(+)-sensitive indicator sodium-binding benzofuran isophthalate and conventional microelectrodes, respectively, at room temperature (24-26 degrees C) while myocytes were stimulated at a rate of 0.25-0.3 Hz. The PKC activator 4beta-phorbol 12-myristate 13-acetate (PMA) decreased a(Na)(i) in a concentration-dependent manner. PMA (100 nM) produced a maximal decrease in a(Na)(i) of 1.5 mM from 6.5 +/- 0.4 to 5.0 +/- 0.4 mM (means +/- SE, n = 12, P < 0.01). The PMA concentration required for a half-maximal decrease in a(Na)(i) was 0.46 +/- 0.13 nM (n = 3, P < 0.01). An inactive phorbol, 4alpha-phorbol 12-myristate 13-acetate, did not decrease a(Na)(i). The decrease caused by PMA could be blocked by the PKC inhibitors staurosporine and bisindolylmaleimide I (GF-109203X). Stimulation of the alpha(1)-adrenoceptor with 50 microM phenylephrine decreased a(Na)(i) from 6.1 +/- 0.3 to 4.6 +/- 0.3 mM (n = 11, P < 0.01). The decrease in a(Na)(i) produced by phenylephrine was blocked by pretreatment with staurosporine, GF-109203X, or PMA. The decrease in a(Na)(i) produced by PMA was not prevented by pretreatment with tetrodotoxin but was blocked by pretreatment with strophanthidin or high extracellular K(+) concentration. The results suggest that alpha(1)-adrenergic receptor activation results in a decrease in a(Na)(i) via PKC-induced stimulation of the Na(+)-K(+) pump in cardiac myocytes.


Assuntos
Membranas Intracelulares/metabolismo , Miocárdio/metabolismo , Proteína Quinase C/fisiologia , Receptores Adrenérgicos alfa/fisiologia , Sódio/metabolismo , Agonistas alfa-Adrenérgicos/farmacologia , Animais , Inibidores Enzimáticos/farmacologia , Espaço Extracelular/metabolismo , Cobaias , Ventrículos do Coração , Indóis/farmacologia , Maleimidas/farmacologia , Miocárdio/citologia , Fenilefrina/farmacologia , Potássio/metabolismo , Proteína Quinase C/antagonistas & inibidores , Sódio/antagonistas & inibidores , Estaurosporina/farmacologia , Estrofantidina/farmacologia , Acetato de Tetradecanoilforbol/farmacologia , Tetrodotoxina/farmacologia
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