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Aims: The present study investigated the vasorelaxant mechanisms of an oral antidiabetic drug, anagliptin, using phenylephrine (Phe)-induced pre-contracted rabbit aortic rings.
Methods: Arterial tone measurement was performed in rabbit thoracic aortic rings.
Results: Anagliptin induced vasorelaxation in a dose-dependent manner. Pre-treatment with the classical voltagedependent K (Kv) channel inhibitors 4-aminopyridine and tetraethylammonium significantly decreased the vasorelaxant effect of anagliptin, whereas pre-treatment with the inwardly rectifying K (Kir) channel inhibitor Ba, the ATP-sensitive K (K) channel inhibitor glibenclamide, and the large-conductance Ca-activated K (BKCa) channel inhibitor paxilline did not attenuate the vasorelaxant effect. Furthermore, the vasorelaxant response of anagliptin was effectively inhibited by pre-treatment with the sarco/endoplasmic reticulum Ca-ATPase (SERCA) pump inhibitors thapsigargin and cyclopiazonic acid. Neither cAMP/protein kinase A (PKA)-related signaling pathway inhibitors (adenylyl cyclase inhibitor SQ 22536 and PKA inhibitor KT 5720) nor cGMP/protein kinase G (PKG)-related signaling pathway inhibitors (guanylyl cyclase inhibitor ODQ and PKG inhibitor KT 5823) reduced the vasorelaxant effect of anagliptin. Similarly, the anagliptin-induced vasorelaxation was independent of the endothelium.
Conclusions: Based on these results, we suggest that anagliptin-induced vasorelaxation in rabbit aortic smooth muscle occurs by activating Kv channels and the SERCA pump, independent of other vascular K channels, cAMP/PKA- or cGMP/PKG-related signaling pathways, and the endothelium.
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http://dx.doi.org/10.1007/s00592-024-02351-9 | DOI Listing |
Biochemistry
September 2025
Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
The sarco-endoplasmic reticulum calcium pump (SERCA) is a P-type ATPase that plays a critical role in intracellular calcium signaling. SERCA maintains the calcium gradient between the cytosol and the sarco-endoplasmic reticulum, which is essential for a variety of physiological events including the muscle contraction-relaxation cycle. In cardiac muscle, SERCA is regulated by transmembrane peptides phospholamban (PLN) and dwarf open reading frame (DWORF).
View Article and Find Full Text PDFbioRxiv
August 2025
Department of Physiology & Membrane Biology, School of Medicine, University of California, Davis, USA.
Pacemaker myocytes of the sinoatrial (SA) node initiate each heartbeat through coupled voltage and Ca oscillators, but whether ATP supply is regulated on a beat-by-beat schedule in these cells has been unclear. Using genetically encoded sensors targeted to the cytosol and mitochondria, we tracked beat-resolved ATP dynamics in intact mouse SA node and isolated myocytes. Cytosolic ATP rose transiently with each Ca transient and segregated into high- and low-gain phenotypes defined by the Ca-ATP coupling slope.
View Article and Find Full Text PDFComput Methods Biomech Biomed Engin
August 2025
Department of Mathematics, S. V. National Institute of Technology, Surat, Gujarat, India.
Calcium () and nitric oxide () play a crucial role in chemical signaling, as regulators of various cellular functions, and as cytotoxic agents under different physiological and pathological settings. These two signaling systems have been investigated in the past as individual systems in pancreatic -cells without considering their spatio-temporal relationships. These studies have generated limited insights, and thus, their role in regulatory and cytotoxic functions of pancreatic -cells is poorly understood.
View Article and Find Full Text PDFFront Physiol
June 2025
Department of Biochemistry, Center for Research and Advanced Studies (Cinvestav) of the National Polytechnic Institute, México City, Mexico.
Prediabetes and Metabolic Syndrome (MetS) share a common pathway to induce vascular dysfunction through hyperinsulinemia without the presence of overt hyperglycemia. Insulin resistance (IR) is a key factor in vascular complications in diabetes; however, vascular dysfunction has been reported in MetS patients, even in the absence of chronic hyperglycemic conditions. We consider that the alterations in the intracellular Ca handling of vascular smooth muscle cells (VSMCs) and the impairment of the insulin receptor signaling pathway may contribute to the etiology of vascular diseases in prediabetes and MetS.
View Article and Find Full Text PDFJ Neurosci
July 2025
Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg 195220, Russia
Alzheimer's disease (AD) is a common neurodegenerative disorder that affects normal neuronal functioning and alters neuronal circuits activity and memory formation and storage. Disrupted neuronal calcium (Ca) signaling is one of the drivers of AD pathogenesis. Previously we suggested that positive allosteric modulators (PAMs) of the sarco/endoplasmic reticulum Ca ATPase (SERCA) pump may help to stabilize cytosolic Ca levels and exert neuroprotective effects in AD neurons.
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