Adjuvant arthritis (AA) is a condition that involves systemic oxidative stress. Unexpectedly, it was found that sarcoplasmic reticulum Ca(2 +)-ATPase (SERCA) activity was elevated in muscles of rats with AA compared to controls, suggesting possible conformational changes in the enzyme. There was no alteration in the nucleotide binding site but rather in the transmembrane domain according to the tryptophan polar/non-polar fluorescence ratio. Higher relative expression of SERCA, higher content of nitrotyrosine but no increase in phospholipid oxidation in AA SR was found. In vitro treatments of SR with HOCl showed that in AA animals SERCA activity was more susceptible to oxidative stress, but SR phospholipids were more resistant and SERCA could also be activated by phosphatidic acid. It was concluded that increased SERCA activity in AA was due to increased levels of SERCA protein and structural changes to the protein, probably induced by direct and specific oxidation involving reactive nitrogen species.
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http://dx.doi.org/10.1080/10715760903089708 | DOI Listing |
Biophys J
January 2025
Department of Pharmacology, University of California Davis, California 95616.
In every heartbeat, cardiac muscle cells perform excitation-Ca signaling-contraction (EC) coupling to pump blood against the vascular resistance. Cardiomyocytes can sense the mechanical load and activate mechano-chemo-transduction (MCT) mechanism, which provides feedback regulation of EC coupling. MCT feedback is important for the heart to upregulate contraction in response to increased load to maintain cardiac output.
View Article and Find Full Text PDFActa Neuropathol Commun
January 2025
Department of Neurology, Mayo Clinic, Rochester, MN, 55905, USA.
Rippling Muscle Disease (RMD) is a rare skeletal myopathy characterized by abnormal muscular excitability manifesting with wave-like muscle contractions and percussion-induced muscle mounding. Hereditary RMD is associated with caveolin-3 or cavin-1 mutations. Recently, we identified cavin 4 autoantibodies as a biomarker of immune-mediated RMD (iRMD), though the underlying disease-mechanisms remain poorly understood.
View Article and Find Full Text PDFChem Biol Interact
January 2025
Department of Biotechnology, Daegu University, Gyeongsan, Gyeongbuk, 38453, Republic of Korea. Electronic address:
Capsaicin, a polyphenol, is known to regulate energy expenditure and thermogenesis in adipocytes and muscles. However, its role in modulating uncoupling proteins (UCPs) and adenosine triphosphate (ATP)-dependent thermogenesis in muscles remains unclear. This study investigated the mechanisms underlying the role of capsaicin in modulating the UCP- and ATP-dependent thermogenesis in C2C12 myoblasts, as well as the gastrocnemius (GM) and soleus muscles (SM) of mice.
View Article and Find Full Text PDFToxicol Appl Pharmacol
January 2025
Institute of Medical Sciences, Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea. Electronic address:
This study explored the vasodilatory mechanisms of the sodium-glucose cotransporter-2 inhibitor remogliflozin using femoral arteries of rabbits. Remogliflozin dilated femoral arterial rings pre-contracted with phenylephrine in a concentration-dependent manner. Pretreatment with the Ca-sensitive K channel inhibitor (paxilline), the ATP-sensitive K channel inhibitor (glibenclamide), or the inwardly rectifying K channel inhibitor (Ba) did not alter the vasodilatory effect.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
January 2025
Smooth Muscle Research Centre, Dundalk Institute of Technology, Dublin Road, Dundalk, Co. Louth, Ireland.
Cholinergic tone is elevated in obstructive lung conditions such as COPD and asthma, but the cellular mechanisms underlying cholinergic contractions of airway smooth muscle (ASM) are still unclear. Some studies report an important role for L-type Ca channels (LTCC) and Ano1 Ca-activated Cl™ channels (CACC) in these responses, but others dispute their importance. Cholinergic contractions of ASM involve activation of M3Rs, however stimulation of M2Rs exerts a profound hypersensitisation of these responses.
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