The possible role of Na+ in the development of hypertension in rats was explored in measurements of intracellular Na+, 22Na efflux, and 3H-ouabain binding sites in resistance vessels and skeletal muscles. In resistance vessels obtained from 13-week-old spontaneously hypertensive rats (SHR) or age-matched Wistar-Kyoto rats (WKY), (Na)i, total or ouabain-resistant 22Na efflux, and the concentration of 3H-ouabain binding sites showed no significant differences. Soleus muscles obtained from 6-week-old and 13-week-old SHR contained 5 to 11% more 3H-ouabain binding sites than those of WKY. The small difference in ouabain binding probably was related more to variations in growth rate and strain than to the hypertension. In SHR and WKY the Na+ and K+ contents of gastrocnemius muscles were almost identical at 6 and 13 weeks of age. By contrast, in Wistar rats in which the (Na)i of skeletal muscle was increased sixfold by K+ depletion, the systolic blood pressure was decreased by 10%. The K+ depletion was associated with a 35 to 55% decrease in the concentration of 3H-ouabain binding sites in both resistance vessels and skeletal muscles. The results provide no support for any simple cause-effect relationships between either elevated (Na)i or altered concentration of 3H-ouabain binding sites and hypertension in SHR.
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http://dx.doi.org/10.1161/01.hyp.7.2.277 | DOI Listing |
Eur J Appl Physiol
August 2020
Institute for Health and Sport (iHeS), Victoria University, PO Box 14428, Melbourne, VIC, 8001, Australia.
Purpose: The Na, K-ATPase (NKA) is important in regulating trans-membrane ion gradients, cellular excitability and muscle function. We investigated the effects of resistance training in healthy young adults on the adaptability of NKA content and of the specific α and β isoforms in human skeletal muscle.
Methods: Twenty-one healthy young males (22.
Front Physiol
August 2016
Clinical Exercise Science Program, Institute of Sport Exercise and Active Living, Victoria University Melbourne, VIC, Australia.
The maintenance of transmembrane Na(+) and K(+) concentration gradients and membrane potential is vital for the production of force in skeletal muscle. In aging an inability to maintain ion regulation and membrane potential would have adverse consequences on the capacity for performing repeated muscle contractions, which are critical for everyday activities and functional independence. This short review focusses on the effects of aging on one major and vital component affecting muscle Na(+) and K(+) concentrations, membrane potential and excitability in skeletal muscle, the Na(+),K(+)-ATPase (Na(+),K(+)-pump, NKA) protein.
View Article and Find Full Text PDFCurr Mol Pharmacol
October 2017
Departamento de Psicobiologia, Universidade Federal de São Paulo, Escola Paulista de Medicina (UNIFESP/ EPM), Rua Botucatu 862, 1° andar, Vila Clementino, São Paulo, SP 04023-062, Brazil.
Background And Objective: Epilepsy is one of the most prevalent neurological disorders worldwide, but its underlying mechanisms have not yet been clarified. Among the possible molecular mechanisms that underlie its occurrence are those that are responsible for the neuronal ionic gradient, including the transmembrane enzyme Na+,K+;-adenosine triphosphatase (ATPase). Na+,K+-ATPase plays an important role in controlling neuronal excitability, and it is believed to be related to the pathophysiology of epilepsy.
View Article and Find Full Text PDFNeurochem Res
June 2016
Instituto de BiologÃa Celular y Neurociencias "Prof. E. De Robertis", CONICET-UBA, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 1121, Buenos Aires, Argentina.
Neurotensin behaves as a neuromodulator or as a neurotransmitter interacting with NTS1 and NTS2 receptors. Neurotensin in vitro inhibits synaptosomal membrane Na(+), K(+)-ATPase activity. This effect is prevented by administration of SR 48692 (antagonist for NTS1 receptor).
View Article and Find Full Text PDFThe Na+-K+-ATPase is specifically inhibited by cardiac glycosides, some of which may also function as endogenous mammalian hormones. Previous studies using Xenopus oocytes, yeast cells, or purified isoforms demonstrated that affinities of various cardiac glycosides for three isoforms of the Na+-K+-ATPase (α1-α3β1) may differ, a finding with potential clinical implication. The present study investigates isoform selectivity and effects of cardiac glycosides on cultured mammalian cells under more physiological conditions.
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