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Effects of strophanthidin on intracellular calcium concentration in ventricular myocytes of guinea pig.
- Source :
-
Yao xue xue bao = Acta pharmaceutica Sinica [Yao Xue Xue Bao] 2008 Mar; Vol. 43 (3), pp. 259-66. - Publication Year :
- 2008
-
Abstract
- Effect of strophanthidin (Str) on intracellular calcium concentration ([Ca2+]i) was investigated on isolated ventricular myocytes of guinea pig. Single ventricular myocytes were obtained by enzymatic dissociation technique. Fluorescent signal of [Ca2+]i was detected with confocal microscopy after incubation of cardiomycytes in Tyrode' s solution with Fluo3-AM. The result showed that Str increased [Ca2+]i in a concentration-dependent manner. The ventricular myocytes began to round-up into a contracture state once the peak level of [Ca2+]i was achieved in the presence of Str (10 micromol L(- 1)), but remained no change in the presence of Str (1 and 100 nmol L(-1)). Tetrodotoxin (TTX), nisodipine, and high concentration of extracellular Ca2+ changed the response of cardiomycytes to Str (1 and 100 nmol L(-1)) , but had no obvious effects on the action of Str (10 micromol L(-1)). The elevation of [Ca2+]i caused by Str at all of the detected concentrations was partially antagonized by rynodine (10 micromol L(-1)) or the removal of Ca2+ from Tyrode's solution. In Na+, K+ -free Tyrode' s solution, the response of cardiomycytes in [Ca2+]i elevation to Str (10 micromol L(-1)) was attenuated, while remained no change to Str (1 and 100 nmol L(-1)). TTX, nisodipine, and high concentration of extracellular Ca2+ changed the response of cardiomycytes to Str at all of the detected concentrations in Na+, K+ -free Tyrode's solution. The study suggests that the elevation of [Ca2+]i by Str at the low (nomomolar) concentrations is partially mediated by the extracellular calcium influx through Ca2+ channel or a "slip mode conductance" of TTX sensitive Na+ channel. While the effect of Str at high (micromolar) concentrations was mainly due to the inhibition of Na+, K+ -ATPase. Directly triggering the release of intracellular Ca2+ from sarcoplasmic reticulum (SR) by Str may be also involved in the mechanism of [Ca2+]i elevation.
- Subjects :
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester pharmacology
Aequorin pharmacology
Animals
Calcium Channel Blockers pharmacology
Fura-2 pharmacology
Fura-2 supply & distribution
Guinea Pigs
Myocardium pathology
Nifedipine pharmacology
Ryanodine pharmacology
Sarcolemma metabolism
Sarcoplasmic Reticulum metabolism
Sodium-Calcium Exchanger
Tetrodotoxin pharmacology
Thapsigargin pharmacology
Calcium metabolism
Calcium Channels metabolism
Sarcolemma pathology
Sarcoplasmic Reticulum drug effects
Sodium-Potassium-Exchanging ATPase antagonists & inhibitors
Strophanthidin pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0513-4870
- Volume :
- 43
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Yao xue xue bao = Acta pharmaceutica Sinica
- Publication Type :
- Academic Journal
- Accession number :
- 18630261