Copyright (c) 2012 S. Karger AG, Basel”
“BACKGROUND AND PURPOSE The role of inosine at the mammalian neuromuscular junction (NMJ) has not been clearly defined.
Moreover, inosine was classically considered to be the inactive metabolite of adenosine. Hence, we investigated the effect of inosine on spontaneous and evoked ACh release, the mechanism underlying its modulatory action and the receptor type and signal transduction pathway SB203580 involved.\n\nEXPERIMENTAL APPROACH End-plate potentials (EPPs) and miniature end-plate potentials (MEPPs) were recorded from the mouse phrenic-nerve diaphragm preparations using conventional intracellular electrophysiological techniques.\n\nKEY RESULTS Inosine (100 mu M) reduced MEPP frequency and the amplitude and quantal content of EPPs; effects inhibited
by the selective A(3) receptor antagonist MRS-1191. Immunohistochemical assays confirmed the presence of A3 receptors at mammalian NMJ. The voltage-gated calcium channel (VGCC) blocker Cd2+, the removal of extracellular Ca2+ and the L-type and P/Q-type VGCC antagonists, nitrendipine and omega-agatoxin IVA, respectively, all prevented inosine-induced inhibition. In the absence of endogenous adenosine, inosine decreased the hypertonic response. The effects of inosine on ACh release were prevented by the G(i/o) protein inhibitor N-ethylmaleimide, PKC antagonist chelerytrine and calmodulin antagonist W-7, but not by PKA antagonists, H-89 and KT-5720, or the inhibitor of CCI-779 CaMKII KN-62.\n\nCONCLUSION AND IMPLICATIONS Our results suggest that, at motor nerve terminals, inosine induces presynaptic inhibition of spontaneous and evoked ACh release by activating A(3) receptors through a mechanism that involves L-type and P/Q-type VGCCs and the secretory machinery downstream of calcium influx. A(3) receptors appear to be coupled Alvocidib solubility dmso to G(i/o) protein. PKC and calmodulin may be involved in these effects of inosine.”
“Background: Chronic renal failure (CRF) is a serious clinical symptom,
occurring as the end result of all kinds of chronic kidney disease and its pathophysiological mechanism is not yet well understood. We investigated the metabolic profiling of urine samples from CRF model rats to find potential disease biomarkers and research pathology of CRF.\n\nMethods: An animal model of CRF was produced by adenine. Metabolic profiling of the urine was performed by using ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC Q-TOF/MS). Acquired data were subjected to principal component analysis (PCA) for differentiating the CRF and the normal control groups. Potential biomarkers were screened by using S-plot and were identified by the accurate mass, isotopic pattern and MSE fragments information obtained from UPLC Q-TOF/MS analysis.