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Effects of photobiomodulation with lowa??level laser therapy on muscle repair following a peripheral nerve injury in Wistar rats
摘要： Introduction: Peripheral nerve injury (PNI) can lead to sensory and/or motor impairment. As a treatment photobiomodulation (PBM) has demonstrated positive effects in terms of the maintenance of muscle activation and trophism. Methods: Wistar rats were divided into five groups: control, injury, injury+PBM, injury+PBMn (irradiation over injured nerve), injury+PBMm (irradiation over affected muscle) and injury+PBMnm (irradiation over nerve and muscle). The left sciatic nerve was submitted to a crushing injury. Treatment was administered with low-level laser (780 nm, 0.04 cm2, 1 W/cm2, 3.2 J) over the injured nerve and/or the tibialis anterior muscle. Results: The effects of PBM were favorable on muscle morphology and gene expression of calcineurin, myogenin and acetylcholine receptors. Conclusion: PBM led to an acceleration on muscle repair process and effects were more evident in two weeks after PNI. Thus, PBM is indicated for the area over both the injured nerve and the affected muscle.
关键词： Regulatory myogenic factors,Photobiomodulation,Nicotinic acetylcholine receptor,Sciatic nerve,Nerve regeneration,Low-level laser therapy
更新于2025-09-16 10:30:52
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Ligand Binding-Induced Structural Changes in the M <sub/>2</sub> Muscarinic Acetylcholine Receptor Revealed by Vibrational Spectroscopy
摘要： M2 muscarinic acetylcholine receptor (M2R) is a prototypical G protein-coupled receptor (GPCR) that responds to acetylcholine and mediates various cellular responses in the nervous system. Here, we used Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy analyses on M2R reconstituted in lipid membrane to understand the molecular mechanism behind the ligand binding-induced conformational changes. Upon agonist binding, M2R shows large spectral change of amide-I band corresponding to backbone C=O stretch, which likely connects with the receptor activation in lipid environment. These results pave the way to probe effects of different ligand binding on GPCRs using vibrational spectroscopy.
关键词： ATR-FTIR spectroscopy,GPCR,M2R,Ligand,acetylcholine
更新于2025-09-12 10:27:22
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Diffracted X-ray Blinking Tracks Single Protein Motions
摘要： Single molecule dynamics studies have begun to use quantum probes. Single particle analysis using cryo-transmission electron microscopy has dramatically improved the resolution when studying protein structures and is shifting towards molecular motion observations. X-ray free-electron lasers are also being explored as routes for determining single molecule structures of biological entities. Here, we propose a new X-ray single molecule technology that allows observation of molecular internal motion over long time scales, ranging from milliseconds up to 103 seconds. Our method uses both low-dose monochromatic X-rays and nanocrystal labelling technology. During monochromatic X-ray diffraction experiments, the intensity of X-ray diffraction from moving single nanocrystals appears to blink because of Brownian motion in aqueous solutions. X-ray diffraction spots from moving nanocrystals were observed to cycle in and out of the Bragg condition. Consequently, the internal motions of a protein molecule labelled with nanocrystals could be extracted from the time trajectory using this diffracted X-ray blinking (DXB) approach. Finally, we succeeded in distinguishing the degree of fluctuation motions of an individual acetylcholine-binding protein (AChBP) interacting with acetylcholine (ACh) using a laboratory X-ray source.
关键词： Acetylcholine-binding protein,Brownian motion,Nanocrystal labelling,Single molecule dynamics,X-ray diffraction
更新于2025-09-09 09:28:46
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LC-MS Supported Studies on the in Vitro Metabolism of both Enantiomers of Flubatine and the in Vivo Metabolism of (+)-[18F]Flubatine—A Positron Emission Tomography Radioligand for Imaging α4β2 Nicotinic Acetylcholine Receptors
摘要： Both enantiomers of [18F]flubatine are promising radioligands for neuroimaging of α4β2 nicotinic acetylcholine receptors (nAChRs) by positron emission tomography (PET). To support clinical studies in patients with early Alzheimer’s disease, a detailed examination of the metabolism in vitro and in vivo has been performed. (+)- and (?)-flubatine, respectively, were incubated with liver microsomes from mouse and human in the presence of NADPH (β-nicotinamide adenine dinucleotide 2′-phosphate reduced tetrasodium salt). Phase I in vitro metabolites were detected and their structures elucidated by LC-MS/MS (liquid chromatography-tandem mass spectrometry). Selected metabolite candidates were synthesized and investigated for structural confirmation. Besides a high level of in vitro stability, the microsomal incubations revealed some species differences as well as enantiomer discrimination with regard to the formation of monohydroxylated products, which was identified as the main metabolic pathway in this assay. Furthermore, after injection of 250 MBq (+)-[18F]flubatine (specific activity > 350 GBq/μmol) into mouse, samples were prepared from brain, liver, plasma, and urine after 30 min and investigated by radio-HPLC (high performance liquid chromatography with radioactivity detection). For structure elucidation of the radiometabolites of (+)-[18F]flubatine formed in vivo, identical chromatographic conditions were applied to LC-MS/MS and radio-HPLC to compare samples obtained in vitro and in vivo. By this correlation approach, we assigned three of four main in vivo radiometabolites to products that are exclusively C- or N-hydroxylated at the azabicyclic ring system of the parent molecule.
关键词： epibatidine,liquid chromatography-mass spectrometry (LC-MS),flubatine,NCFHEB,liver microsomes,nicotinic acetylcholine receptors (nAChRs),radiometabolites,positron emission tomography (PET)
更新于2025-09-04 15:30:14