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Relationship between cardiotonic effects and inhibition on cardiac sarcolemmal Na+,K+-ATPase of strophan-thidin at low concentrations.
- Source :
-
Acta pharmacologica Sinica [Acta Pharmacol Sin] 2003 Nov; Vol. 24 (11), pp. 1103-7. - Publication Year :
- 2003
-
Abstract
- Aim: To evaluate the effects of strophanthidin (Str) on cardiac contractile function and sarcolemmal Na+, K+-ATPase activities in isolated guinea-pig hearts.<br />Methods: Isolated guinea-pig hearts were perfused through aorta in a Langendorff mode. Heart rate (HR), left ventricular pressure (LVP), and first derivatives (+/-dp/dt(max)) of LVP were recorded by eight-channel physiological instrument. Cardiac sarcolemmal Na+, K+-ATPase activities were determined with colorimetry.<br />Results: Str 0.1 nmol/L stimulated the Na+, K+-ATPase activities (P<0.05), but had no effect on HR, LVP, and +/-dp/dt(max). Str 1 nmol/L increased +dp/dt(max) (P<0.05) and Na+, K+-ATPase activities (P<0.01). Str 10 and 100 nmol/L significantly increased both LVP (P<0.05) and +dp/dt(max) (P<0.05 or P<0.01), and had no significant effects on Na+, K+-ATPase activities. However, Str 1-100 micromol/L at first enhanced the LVP and +dp/dtmax (P<0.01), then reduced them resulting from irregular contraction, and effects of Str on Na+, K+-ATPase activities revealed a concentration-dependent inhibition (P<0.01).<br />Conclusion: The positive inotropic effects and irregular contraction produced by Str at higher concentrations result from the inhibition of Na+, K+-ATPase activities, and the positive inotropic effects of Str at lower concentrations are not related to the inhibition of the Na+, K+-ATPase activities.
- Subjects :
- Animals
Blood Pressure drug effects
Cardiotonic Agents administration & dosage
Female
Guinea Pigs
Heart Rate drug effects
In Vitro Techniques
Male
Myocardium cytology
Sarcolemma enzymology
Strophanthidin administration & dosage
Cardiotonic Agents pharmacology
Myocardial Contraction drug effects
Myocardium enzymology
Sodium-Potassium-Exchanging ATPase metabolism
Strophanthidin pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 1671-4083
- Volume :
- 24
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Acta pharmacologica Sinica
- Publication Type :
- Academic Journal
- Accession number :
- 14627493