Short-term NO synthase inhibition and the Na+ - binding properties of cardiac Na,K-ATPase

Title:

Short-term NO synthase inhibition and the Na+ - binding properties of cardiac Na,K-ATPase

Creator:

Vrbjar, N., Monika Ivanová, Oľga Pecháňová, and Mária Gerová

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:a5115ac4-5f2c-48eb-89d8-f2104d07c1e5
uuid:a5115ac4-5f2c-48eb-89d8-f2104d07c1e5
issn:0862-8408

Subject:

Fyziologie člověka a srovnávací fyziologie, srdce, oxid dusnatý, heart, nitric oxide, pressure overload, L-NAME, 14, and 612

Type:

article, články, model:article, and TEXT

Format:

print, bez média, and svazek

Description:

It is known that hypertension is accompanied by increased [Na+]i. The functional properties of Na,K-ATPase, which transports the Na+ out and K+ into myocardial cells during the relaxation phase, were investigated in the left ventricle (LV), septum (SV) and the right ventricle (RV) of anesthetized dogs with moderate acute blood pressure elevation elicited by short-term (4-hour) NO synthase inhibition. The NO-insufficiency was induced by administration of an L-arginine analogue, the NG-nitro-L-arginine methyl ester (L-NAME). Concerning the function of Na,K-ATPase under the conditions of lowered NO synthesis, we focused our attention to the binding of Na+ to the enzyme molecule. Activation of the enzyme by increasing Na+ concentrations revealed significant changes in both the maximal velocity (Vmax) and the affinity for Na+ (KNa) in all investigated heart sections. The Vmax increased by 27 % in LV, by 87 % in SV and by 58 % in RV. The KNa value increased by 86 % in LV, by 105 % in SV and by 93% in RV, indicating an apparent decrease in the sensitivity of the Na+-binding site in the Na,K-ATPase molecule. This apparently decreased pump affinity for Na+ together with the increase of Vmax suggest that, during the short-term inhibition of NO synthesis, the Na,K-ATPase is capable of extruding the excessive Na+ from the myocardial cells more effectively at higher [Na+]i as compared to the Na,K-ATPase of control animals., N. Vrbjar, M. Strnisková, O. Pecháňová, M. Gerová., and Obsahuje bibliografii

Language:

English

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Source:

Physiological research | 2000 Volume:49 | Number:1

Harvested from:

CDK

Metadata only:

false