Pharmacological research : the official journal of the Italian Pharmacological Society
-
Both peptidic agonist exenatide and herbal agonist catalpol of the glucagon-like peptide-1 receptor (GLP-1R) are neuroprotective. We have previously shown that activation of spinal GLP-1Rs expresses β-endorphin in microglia to produce antinociception. The aim of this study was to explore whether exenatide and catalpol exert neuroprotection via activation of the hippocampal GLP-1R/β-endorphin pathway. ⋯ Furthermore, exenatide and catalpol neuroprotection was completely blocked by i.c.v. injection of the GLP-1R orthosteric antagonist exendin (9-39), specific β-endorphin antiserum, and selective opioid receptor antagonist naloxone. Our results indicate, for the first time, that the neuroprotective effects of catalpol and exenatide are GLP-1R-specific, and that these effects are mediated by β-endorphin expression probably in hippocampal microglia. We postulate that in contrast to the peripheral tissue, where the activation of GLP-1Rs in pancreas islet β-cells causes secretion of insulin to perform glucoregulation, it leads to β-endorphin expression in microglial cells to produce neuroprotection and analgesia in the central nervous system.
-
Protein kinases play a predominant regulatory role in nearly every aspect of cell biology and they can modify the function of a protein in almost every conceivable way. Protein phosphorylation can increase or decrease enzyme activity and it can alter other biological activities such as transcription and translation. Moreover, some phosphorylation sites on a given protein are stimulatory while others are inhibitory. ⋯ However, the near universal and expected development of drug resistance in the treatment of neoplastic disorders requires new approaches to solve this therapeutic challenge. Cancer is the predominant indication for these drugs, but disease targets are increasing. For example, we can expect the approval of new drugs inhibiting other protein kinases in the treatment of illnesses such as hypertension, Parkinson's disease, and autoimmune diseases.
-
Transient Receptor Potential (TRP) cation channels, such as TRP Vanilloid 1 and TRP Ankyrin repeat domain 1 (TRPV1 and TRPA1) are nocisensors playing important role to signal pain. Two "melastatin" TRP receptors, like TRPM8 and TRPM3 are also expressed in a subgroup of primary sensory neurons. These channels serve as thermosensors with unique thermal sensitivity ranges and are activated also by several exogenous and endogenous chemical ligands inducing conformational changes from various allosteric ("multisteric") sites. ⋯ Besides the cell bodies, SMase also inhibited capsaicin- or AITC-evoked CGRP release from peripheral sensory nerve terminals, this provides the first evidence for the importance of lipid raft integrity in TRPV1 and TRPA1 gating on capsaicin-sensitive nerve terminals. SM metabolites, ceramide and sphingosine, did not influence TRPA1 and TRPV1 activation on TRG neurons, TRPV1-expressing CHO cell line, and nerve terminals. We suggest, that the hydrophobic interactions between TRP receptors and membrane lipid raft interfaces modulate the opening properties of these channels and therefore, targeting this interaction might be a promising tool for drug developmental purposes.
-
We have previously demonstrated that activation of the spinal sigma-1 receptor (Sig-1R) plays an important role in the development of mechanical allodynia (MA) via secondary activation of the N-methyl-d-aspartate (NMDA) receptor. Sig-1Rs have been shown to localize to astrocytes, and blockade of Sig-1Rs inhibits the pathologic activation of astrocytes in neuropathic mice. However, the mechanism by which Sig-1R activation in astrocytes modulates NMDA receptors in neurons is currently unknown. d-serine, synthesized from l-serine by serine racemase (Srr) in astrocytes, is an endogenous co-agonist for the NMDA receptor glycine site and can control NMDA receptor activity. ⋯ Finally, BD-1047 administration inhibited the development of MA and this inhibition was reversed by intrathecal treatment with exogenous d-serine. These findings demonstrate for the first time that the activation of Sig-1Rs increases the expression of Srr and d-serine in astrocytes. The increased production of d-serine induced by CCI ultimately affects dorsal horn neurons that are involved in the development of MA in neuropathic mice.
-
Meta Analysis
Statin therapy and plasma coenzyme Q10 concentrations--A systematic review and meta-analysis of placebo-controlled trials.
Statin therapy may lower plasma coenzyme Q10 (CoQ10) concentrations, but the evidence as to the significance of this effect is unclear. We assessed the impact of statin therapy on plasma CoQ10 concentrations through the meta-analysis of available RCTs. The literature search included selected databases up to April 30, 2015. ⋯ With respect to treatment duration, a significant effect was observed in both subsets of trials lasting <12 weeks (WMD: -0.51 μmol/L, 95%CI: -0.64, -0.39, p<0.001) and ≥12 weeks (WMD: -0.40 μmol/L, 95%CI: -0.50, -0.30, p<0.001). The meta-analysis showed a significant reduction in plasma CoQ10 concentrations following treatment with statins. Further well-designed trials are required to confirm our findings and elucidate their clinical relevance.