An endogenous ouabain-like factor (EOLF) was measured in brain tissue of cats 12 and 24 hrs after cold injury-induced edema. EOLF was assayed via its inhibition of 86Rb+ uptake in human red blood cells in a fraction which was obtained from brain tissue by methanol extraction, chloroform treatment and purification of the water phase by C-18 HPLC. As compared to the contralateral hemispheres with an EOLF concentration of 605 +/- 71 pmol ouabain equivalents per g wet weight, the edematous hemisphere had significantly higher concentrations: 12 hours after cold injury it was 2600 +/- 1762 pmol (p < 0.03) and fell to 857 +/- 160 pmol ouabain equivalents/g wet weight after 24 hrs. Similar kinetics were evident for the EOLF concentrations in cerebrospinal fluid. It is suggested that the increase of EOLF in the edematous brain hemisphere may participate as a mediator in the development of vasogenic brain edema in the disturbance of the sodium metabolism.
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http://dx.doi.org/10.1007/978-3-7091-9334-1_25 | DOI Listing |
Cell Calcium
March 2020
Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
In this brief review we discuss some aspects of the Na pump and its roles in mediating the effects of ouabain and endogenous ouabain (EO): i) in regulating the cytosolic Ca concentration ([Ca]) via Na/Ca exchange (NCX), and ii) in activating a number of protein kinase (PK) signaling cascades that control a myriad of cell functions. Importantly, [Ca] and the other signaling pathways intersect at numerous points because of the influence of Ca and calmodulin in modulating some steps in those other pathways. While both mechanisms operate in virtually all cells and tissues, this article focuses primarily on their functions in the cardiovascular system, the central nervous system (CNS) and the kidneys.
View Article and Find Full Text PDFCurr Top Membr
June 2020
Department of Biomedicine, Health, Aarhus University, Aarhus, Denmark. Electronic address:
The Na,K-ATPase is an enzyme essential for ion homeostasis in all cells. Over the last decades, it has been well-established that in addition to the transport of Na/K over the cell membrane, the Na,K-ATPase acts as a receptor transducing humoral signals intracellularly. It has been suggested that ouabain-like compounds serve as endogenous modulators of this Na,K-ATPase signal transduction.
View Article and Find Full Text PDFPLoS One
February 2020
Huntington Medical Research Institutes, Pasadena, California, United States of America.
There is strong evidence that neuronal hyper-excitability underlies migraine, and may or may not be preceded by cortical spreading depression. However, the mechanisms for cortical spreading depression and/or migraine are not established. Previous studies reported that cerebrospinal fluid (CSF) [Na+] is higher during migraine, and that higher extracellular [Na+] leads to hyper-excitability.
View Article and Find Full Text PDFInsects
April 2019
Department of Psychiatry and Behavioral Sciences, University of Louisville School of Medicine, Louisville, KY 40202, USA.
Cardiac glycosides, cardenolides and bufadienolides, are elaborated by several plant or animal species to prevent grazing or predation. Entomologists have characterized several insect species that have evolved the ability to sequester these glycosides in their tissues to reduce their palatability and, thus, reduce predation. Cardiac glycosides are known to interact with the sodium- and potassium-activated adenosine triphosphatase, or sodium pump, through a specific receptor-binding site.
View Article and Find Full Text PDFAutism Res
October 2018
From the Department of Experimental, Diagnostic, and Specialty Medicine, University of Bologna, Bologna, Italy.
Na , K -ATPase (NKA) activity, which establishes the sodium and potassium gradient across the cell membrane and is instrumental in the propagation of the nerve impulses, is altered in a number of neurological and neuropsychiatric disorders, including autism spectrum disorders (ASD). In the present work, we examined a wide range of biochemical and cellular parameters in the attempt to understand the reason(s) for the severe decrease in NKA activity in erythrocytes of ASD children that we reported previously. NKA activity in leukocytes was found to be decreased independently from alteration in plasma membrane fluidity.
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