Journal of pharmacological sciences
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Development of next-generation analgesics requires a better understanding of the molecular and cellular mechanisms underlying pathological pain. Accumulating evidence suggests that the activation of glia contributes to the central sensitization of pain signaling in the spinal cord. The role of microglia in pathological pain has been well documented, while that of astrocytes still remains unclear. ⋯ Although astrocyte-to-neuron signals implicated in pathological pain is poorly understood, activated astrocytes, as well as microglia, produce proinflammatory cytokines and chemokines, which lead to adaptation of the dorsal horn neurons. Furthermore, it has been suggested that glial glutamate transporters in the spinal astrocytes are down-regulated in pathological pain and that up-regulation or functional enhancement of these transporters prevents pathological pain. This review will briefly discuss novel findings on the role of spinal astrocytes in pathological pain and their potential as a therapeutic target for novel analgesics.
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Recent randomized controlled trials showed that blockade of the renin-angiotensin system (RAS) by angiotensin-converting enzyme (ACE) inhibitors and angiotensin II-receptor blockers (ARBs) reduced cardiovascular and renal events. These drugs are widely used in the management of cardiovascular and renal diseases. Results from Randomized Controlled Trials (RCTs) so far, however, also raise several questions to be addressed. ⋯ Such insufficient efficacy of RAS inhibition may result from the fact that neither ACE inhibitors nor ARBs completely suppress activity of RAS. Since then effort has been made to determine whether the dual blockade of RAS could provide further improvement in cardiovascular and renal outcome. This review extracts unsolved questions in the treatment with RAS inhibitors from outcome studies and discusses them from the clinical pharmacological point of view.
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Sepsis remains the leading cause of death in critically ill patients. A major problem contributing to sepsis-related high mortality is the lack of effective medical treatment. ⋯ The pivotal role of cell apoptosis is now highlighted by multiple studies demonstrating that prevention of cell apoptosis can improve survival in clinically relevant animal models of sepsis. In this review article, we address the scientific rationale for remedying apoptotic cell death in sepsis and propose that therapeutic efforts aimed at blocking cell signaling pathways leading to apoptosis may represent an attractive target for sepsis therapy.
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Tissue-type plasminogen activator (t-PA) administration has been approved for treating acute ischemic stroke, but delayed treatment is associated with increased risk of cerebral hemorrhage and brain injury. t-PA, a serine proteinase, converts plasminogen to plasmin. Plasmin participates not only in the degradation of fibrin, causing clot lysis, but also in the degradation of various extracellular matrix proteins, either directly or via the activation of matrix metalloproteinase (MMPs). We established an animal stroke model and observed a phenomenon of spontaneous rethrombosis and thrombolysis in the cerebral vessels after vessel damage. ⋯ On studying intracranial hemorrhage (ICH) induced by t-PA treatment of ischemic stroke, we observed that MMP-3 is relatively important for the enhanced ICH induced by t-PA. MMP-3 was upregulated by t-PA in endothelial cells, but the upregulation was prevented by the inhibition of either low-density lipoprotein receptor-related protein (LRP) or nuclear factor kappa-B (NF-kappaB) activation. Thus, t-PA causes ICH via MMP-3 induction in endothelial cells, which is regulated through the LRP/NF-kappaB pathway, and could be targeted to improve the therapeutic efficacy of t-PA for acute ischemic stroke.
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G protein-coupled receptors, in particular, Ca(2+)-mobilizing G(q)-coupled receptors have been reported to be targets for anesthetics. Opioids are commonly used analgesics in clinical practice, but the effects of anesthetics on the opioid mu-receptors (muOR) have not been systematically examined. We report here an electrophysiological assay to analyze the effects of anesthetics and ethanol on the functions of muOR in Xenopus oocytes expressing a muOR fused to chimeric Galpha protein G(qi5) (muOR-G(qi5)). ⋯ Propofol and halothane inhibited the DAMGO-induced currents only at higher concentrations. These findings suggest that ketamine and ethanol may inhibit muOR functions in clinical practice. We propose that the electrophysiological assay in Xenopus oocytes expressing muOR-G(qi5) would be useful for analyzing the effects of anesthetics and analgesics on opioid receptor function.