Your browser doesn't support javascript.
loading
Extract from leaf of Psidium guajava L depresses the guinea pig atrial contractility by interfering with potassium and calcium channels / Extrato de folha de Psidium guajava L deprime a contratilidade atrial de cobaia, interferindo com os canais de potássio e cálcio
Gondim, Antonio Nei Santana; Oliveira, Vanda Rodrigues de; Santos, Sellyanna Domeny dos; Silva, Bagnólia Araújo da; Vasconcelos, Carla Maria Lins de; Conde-Garcia, Eduardo Antonio.
  • Gondim, Antonio Nei Santana; Federal University of Sergie. Department of Physiology. Laboratory of Heart Biophysics. BR
  • Oliveira, Vanda Rodrigues de; Federal University of Sergie. Department of Physiology. Laboratory of Heart Biophysics. BR
  • Santos, Sellyanna Domeny dos; Federal University of Sergie. Department of Physiology. Laboratory of Heart Biophysics. BR
  • Silva, Bagnólia Araújo da; Federal University of Paraíba. Laboratory of Pharmaceutical Technology Prof. Delby Fernandes de Medeiros. BR
  • Vasconcelos, Carla Maria Lins de; Federal University of Sergie. Department of Physiology. Laboratory of Heart Biophysics. BR
  • Conde-Garcia, Eduardo Antonio; Federal University of Sergie. Department of Physiology. Laboratory of Heart Biophysics. BR
Braz. j. pharm. sci ; 45(3): 483-489, July-Sept. 2009. graf, ilus
Article in English | LILACS | ID: lil-533176
ABSTRACT
The negative inotropic effect of aqueous fraction (AqF) obtained from the acetic extract of Psidium guajava L leaf was investigated on the guinea pig left atrium. Myocardial force was measured isometrically (27 ± 0.1 ºC, 2 Hz). AqF (100 μg/ml) reduced contractility of about 85 ± 9.4 percent (n = 4, p < 0.001, Fcalc = 51.70, F(0.01; 4; 21) = 5.09, EC50 = 14.28 ± 3 μg/mL) in a concentration-dependent fashion. This effect was reduced by 20 mM of tetraethylammonium (TEA), increasing EC50 to 50 ± 7 μg/ml (n = 4, p < 0.001, Fcalc = 282.13; F(0.01; 21; 66) = 2.36). AqF (100 μg/ml) shifted to the right the CaCl2 concentration-effect curve, increasing the EC50 from 2170 ± 112 to 2690 ± 132 μM (n = 3, p < 0.001, Fcalc = 220.80 ; F(0.01; 29; 60) = 2.19). L-NAME (100 μM) did not modify the AqF inotropic effect (n = 3, p > 0.05) sugesting that the oxide nitric pathway did not participate of the action mechanism of AqF. We can conclude that AqF depresses the atrial contractile by reducing the calcium entry in myocardial cells and also by openenig potassium channels of cardiac tissue.
RESUMO
O efeito inotrópico da fração aquosa (AqF) do extrato acético das folhas de Psidium guajava L. foi investigado em átrio esquerdo de cobaia. A força miocárdica foi medida isometricamente (27 ± 0,1 ºC; 2 Hz). A AqF (100 μg/mL) reduziu a contratilidade em até 85 ± 9,4 por cento (n = 4; p < 0,001; Fcalc = 51,70; F(0,01; 4; 21) = 5,09; CE50 = 14,28 ± 3 μg/mL) de forma dependente da concentração. Este efeito foi reduzido pelo tetraetilamônio (TEA, 20 mM) que também aumentou a CE50 de 14,28 ± 3 μg/mL para 50 ± 7 μg/mL (n = 4; p < 0,001; Fcalc = 282,13; F(0,01; 21; 66) = 2,36). A AqF (100 μg/mL) deslocou para a direita a curva concentração-efeito do CaCl2, aumentando a CE50 de 2170 ± 112 para 2690 ± 132 μM (n = 3; p < 0,001; Fcalc = 220,80 ; F(0,01; 29; 60) = 2,19). Por outro lado, o L-NAME (100 μM) não alterou o efeito inotrópico da AqF (n = 3; p > 0,05), sugerindo que a via do óxido nítrico não participa do mecanismo de ação da AqF. Conclui-se que a AqF deprime a contratilidade atrial por reduzir a entrada de cálcio nas células miocárdicas e por abrir canais de potássio deste tecido.
Subject(s)

Full text: Available Index: LILACS (Americas) Main subject: Plant Extracts / Calcium Channels / Potassium Channels / Psidium / Heart Atria Type of study: Evaluation studies Limits: Animals Language: English Journal: Braz. j. pharm. sci Year: 2009 Type: Article / Project document Affiliation country: Brazil Institution/Affiliation country: Federal University of Paraíba/BR / Federal University of Sergie/BR

Similar

MEDLINE

...
LILACS

LIS

Full text: Available Index: LILACS (Americas) Main subject: Plant Extracts / Calcium Channels / Potassium Channels / Psidium / Heart Atria Type of study: Evaluation studies Limits: Animals Language: English Journal: Braz. j. pharm. sci Year: 2009 Type: Article / Project document Affiliation country: Brazil Institution/Affiliation country: Federal University of Paraíba/BR / Federal University of Sergie/BR