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1.
Rev. bras. plantas med ; 16(4): 819-825, oct.-dic. 2014. graf
Artigo em Inglês | LILACS | ID: lil-729889

RESUMO

Electrocardiographic effects produced by Ginkgo biloba extract (EGb) and by ginkgolides A (GA) and B (GB), and bilobalide (BB) were investigated in guinea pig heart mounted in Langendorff apparatus (Tyrode, 34 ± 0.1 ºC, 95% O2, 5% CO2). Electrocardiographic parameters were evaluated in the conditions: 1) control with Tyrode and DMSO, 2) EGb (n=4), GA (n=5), GB (n=5) or BB (n=6), and 3) washout. The results showed that 0.1 and 1.0 mg/ml of EGb do not change the electrocardiographic parameters. However, 10 mg/ml of EGb increased the PR interval (PRi) at 21% (p<0.001). This increase was also observed for 50 mM GA (20%, p<0.001) and 70 mM BB (13%, p<0.001), which indicates Ca2+ channel block. However, the 50 mM GB reduced the PRi at 11 % (p<0.001). The GA (23%, p<0.001), GB (16%, p<0.001), and BB (40%, p<0.001) reduced the QT interval (QTi), which suggests the activation of the potassium channel. However, EGb increased QTi (6%, p<0.001). The EGb (28%, p<0.05) and GB (13%, p<0.05) reduced the heart rate. Atrioventricular (AV) block was observed with EGb, GA, and BB. We can conclude that EGb and its terpenoids alter the ECG parameters inducing AV block, which indicates possible arrhythmogenic potential.


Os efeitos eletrocardiográficos produzidos pelo extrato de Ginkgo biloba (EGb) e gingkolídeos A (GA) e B (GB), e bilobalide (BB) foram investigados em coração de cobaia montado sistema de Langendorff (Tyrode, 34 ± 0.1 ºC, 95% O2, 5% CO2). Os parâmetros do ECG foram avaliados nas condições: 1) Tyrode e DMSO, 2) EGb (n=4), GA (n=5), GB (n=5) ou BB (n=6) diluídos em DMSO e 3) washout. Os resultados demonstram que 0,1 e 1,0 mg/mL de EGb não alteraram os parâmetros eletrocardiográficos. Entretanto, 10 mg/ml de EGb aumentaram o intervalo PR (PRi) em 21% (p<0.001). Esse aumento também foi observado com GA a 50µM (20%, p<0,001) e BB a 70 mM (13%, p<0,001) indicando bloqueio de canais de cálcio. Por outro lado, GB reduziu o PRi (11%, p<0,001). O intervalo QT (QTi) foi reduzido por GA (23%, p<0,001), GB (16%, p<0,001) e BB (40%, p < 0.001) sugerindo uma ativação de canais de potássio. Entretanto, EGb aumentou o QTi (6%, p<0.001). A frequência cardíaca foi reduzida por EGb (28%, p<0.05) e GB (13%, p<0.05). Bloqueios átrio-ventriculares (BAV) foram observados com EGb, GA e BB. Podemos concluir que EGb e os terpenos alteram parâmetros eletrocardiográficos induzindo BAV e demonstrando possível potencial arritmogênico.


Assuntos
Cobaias , Eletrocardiografia/estatística & dados numéricos , Ginkgo biloba/efeitos adversos , Extratos Vegetais/antagonistas & inibidores , Terpenos/análise , Bilobalídeos/farmacologia , Ginkgolídeos/análise , Coração/efeitos dos fármacos
2.
Braz J Med Biol Res ; 38(1): 111-8, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15665997

RESUMO

The objective of the present investigation was to determine the contractile effect of crude and acetone leaf extracts of Citrus sinensis (L.) Osb. on mammalian myocardium. Crude leaf extracts have been used in folk medicine to treat neurological disorders. Some flavonoids isolated from this plant presented a positive inotropic effect on myocardium. This motivated us to test the extracts on the atria of guinea pigs of both sexes (300-500 g) and surprisingly we observed inotropic depression instead of an increase in force. The maximum effect of the crude extract was 79.4 +/- 8.1% of the control force amplitude (N = 5 hearts, 10 trials, 27 +/- 0.1 degrees C, stimulus: 2 Hz, 400 V, 0.5 ms). The EC50 for crude, ethanol, acetic, aqueous, and acetone extracts was 300, 300, 600, 1000, and 140 microg/ml, respectively, with a Hill constant of 1.8, 2.0, 2.5, 2.0, and 1.4, respectively. Blockade of cholinergic, beta-adrenergic, or opioid membrane receptors with 1.5 microM atropine sulfate, 1 microM propranolol, and 10 microM naloxone, respectively, did not change the effect of the crude extract. The acetone extract abolished the Bowditch positive staircase phenomenon (N = 5 hearts, 10 trials, 27 +/- 0.1 degrees C), suggesting a possible reduction of the calcium inward current, and also promoted the so-called Woodworth phenomenon. The effect was concentration-dependent and indicated the existence of another inhibitory contractile mechanism such as the simultaneous activation of some of the membrane potassium channels reducing the myocardial action potential duration and further decreasing the cellular calcium entry.


Assuntos
Cardiotônicos/farmacologia , Citrus sinensis/química , Contração Miocárdica/efeitos dos fármacos , Animais , Feminino , Cobaias , Átrios do Coração/efeitos dos fármacos , Masculino , Extratos Vegetais/farmacologia , Folhas de Planta
3.
Braz. j. med. biol. res ; 38(1): 111-118, Jan. 2005. graf
Artigo em Inglês | LILACS | ID: lil-405540

RESUMO

The objective of the present investigation was to determine the contractile effect of crude and acetone leaf extracts of Citrus sinensis (L.) Osb. on mammalian myocardium. Crude leaf extracts have been used in folk medicine to treat neurological disorders. Some flavonoids isolated from this plant presented a positive inotropic effect on myocardium. This motivated us to test the extracts on the atria of guinea pigs of both sexes (300-500 g) and surprisingly we observed inotropic depression instead of an increase in force. The maximum effect of the crude extract was 79.4 ± 8.1 percent of the control force amplitude (N = 5 hearts, 10 trials, 27 ± 0.1°C, stimulus: 2 Hz, 400 V, 0.5 ms). The EC50 for crude, ethanol, acetic, aqueous, and acetone extracts was 300, 300, 600, 1000, and 140 æg/ml, respectively, with a Hill constant of 1.8, 2.0, 2.5, 2.0, and 1.4, respectively. Blockade of cholinergic, beta-adrenergic, or opioid membrane receptors with 1.5 æM atropine sulfate, 1 æM propranolol, and 10 æM naloxone, respectively, did not change the effect of the crude extract. The acetone extract abolished the Bowditch positive staircase phenomenon (N = 5 hearts, 10 trials, 27 ± 0.1°C), suggesting a possible reduction of the calcium inward current, and also promoted the so-called Woodworth phenomenon. The effect was concentration-dependent and indicated the existence of another inhibitory contractile mechanism such as the simultaneous activation of some of the membrane potassium channels reducing the myocardial action potential duration and further decreasing the cellular calcium entry.


Assuntos
Animais , Masculino , Feminino , Cobaias , Citrus sinensis , Cardiotônicos/farmacologia , Contração Miocárdica/efeitos dos fármacos , Átrios do Coração/efeitos dos fármacos , Folhas de Planta , Extratos Vegetais/farmacologia
4.
Eur J Pediatr Surg ; 6(2): 110-1, 1996 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8740136

RESUMO

A boy underwent liver transplantation for postnecrotic cirrhosis secondary to Wilson's disease. The patient had no neurological clinical manifestations prior to the transplantation. The patient developed dysarthria, dysphagia, spasticity, rigidity, and intention and resting tremor of all extremities. Cranial computerized tomography revealed hypodensity of the thalamus, basal ganglia and external capsule. Anti-cytomegalovirus IgM became positive. At autopsy, there were severe pathological changes at the thalamus and basal ganglia.


Assuntos
Doenças dos Gânglios da Base/etiologia , Infecções por Citomegalovirus/complicações , Transplante de Fígado , Complicações Pós-Operatórias , Toxoplasmose Cerebral/complicações , Adolescente , Degeneração Hepatolenticular/cirurgia , Humanos , Cirrose Hepática/cirurgia , Masculino
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