Antithrombin reduces reperfusion-induced liver injury in mice by enhancing sensory neuron activation

2006 ◽  
Vol 95 (05) ◽  
pp. 788-795 ◽  
Author(s):  
Naoaki Harada ◽  
Mitsuhiro Uchiba ◽  
Hiroki Kurihara ◽  
Naomi Nakagata ◽  
Kenji Okajima
Keyword(s):  
Liver Injury ◽  
Sensory Neuron ◽  
Sensory Neurons ◽  
Ischemia Reperfusion ◽  
Dorsal Root Ganglion Neurons ◽  
Hepatic Tissue ◽  
Tissue Levels ◽  
Cgrp Release ◽  
Neuron Activation ◽  
Ganglion Neurons

SummaryWe recently demonstrated that antithrombin (AT) reduces ischemia/reperfusion (I/R)-induced liver injury in rats by increasing hepatic tissue levels of calcitonin gene-related peptide (CGRP),a neuropeptide released from the sensory nerve endings. In the present study, we examined the effect of AT on I/Rinduced liver injury in wild type mice (CGRP+/+) and congenitally αCGRP-deficient mice (CGRP−/−). We also investigated any effects of AT on CGRP release from dorsal root ganglion neurons (DRG) isolated from CGRP+/+. Based on results obtained in the present study, we attempted to determine if the anti-inflammatory activity of AT in vivo is dependent mainly on sensory neuron activation. AT enhanced ischemia/reperfusion-induced increases in hepatic tissue levels of CGRP and 6-keto-PGF1α , a stable metabolite of PGI2, in CGRP+/+, but it did not enhance these increases in CGRP−/−. AT inhibited reperfusion-induced increases in serum alanine aminotransferase levels by increasing hepatic tissue blood flow and by attenuating increases in hepatic levels of tumor necrosis factor and myeloperoxidase in CGRP+/+,although it showed neither of these therapeutic effects in CGRP−/−. AT increased CGRP release from cultured DRGs only in the presence of anandamide, and AT-induced increase in CGRP release was not observed in the presence KT5720, an inhibitor of protein kinase A (PKA).AT markedly increased intracellular levels of cAMP in the presence of anandamide. These results strongly suggest that AT might reduce I/R-induced liver injury by enhancing activation of the sensory neurons through activation of PKA in sensory neurons.

Contribution of capsaicin-sensitive sensory neurons to antithrombin-induced reduction of ischemia/reperfusion-induced liver injury in rats

2005 ◽  
Vol 93 (01) ◽  
pp. 48-56 ◽  
Author(s):  
Naoaki Harada ◽  
Mehtap Yuksel ◽  
Hirotaka Isobe ◽  
Kenji Okajima
Keyword(s):  
Liver Injury ◽  
Sensory Neurons ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion ◽  
Dorsal Root Ganglion Neurons ◽  
Hepatic Tissue ◽  
Tissue Blood Flow ◽  
Tissue Levels ◽  
Neuron Activation ◽  
Ganglion Neurons

SummaryWe previously reported that antithrombin (AT) reduced ischemia/ reperfusion (I/R)-induced liver injury in rats by increasing endothelial production of prostacyclin (PGI2). However, the mechanism(s) underlying this phenomenon remains to be fully elucidated. We also demonstrated that activation of capsaicinsensitive sensory neurons increased endothelial production of PGI2 by releasing calcitonin gene-related peptide (CGRP) in rats subjected to hepatic I/R. In the present study, we investigated whether AT increases endothelial production of PGI2 through activation of the sensory neurons in rats subjected to hepatic I/R. AT significantly enhanced the I/R-induced increases in hepatic tissue levels of CGRP in rats. Increases in hepatic tissue levels of 6-keto-PGF1α, a stable metabolite of PGI2 , the increase in hepatic-tissue blood flow, and attenuation of both hepatic local inflammatory responses and liver injury in rats administered AT were completely reversed by administration of capsazepine, an inhibitor of sensory neuron activation and CGRP(8–37), a CGRP antagonist.AT did not show any protective effect on liver injury in animals undergoing functional denervation by administration of a large amount of capsaicin.AT significantly increased CGRP release from cultured dorsal root ganglion neurons isolated from rats in the presence of capsaicin.Taken together,these observations strongly suggested that AT might increase hepatic tissue levels of PGI2 via enhancement of hepatic I/R-induced activation of capsaicin-sensitive sensory neurons,thereby reducing liver injury in rats. In this process, CGRP-induced activation of both endothelial nitric oxide synthase and cyclooxygenase-1 might be critically involved.

Danaparoid sodium reduces ischemia/reperfusion-induced liver injury in rats by attenuating inflammatory responses

2007 ◽  
Vol 97 (01) ◽  
pp. 81-87 ◽  
Author(s):  
Naoaki Harada ◽  
Hidefumi Kohmura ◽  
Mitsuhiro Uchiba ◽  
Tsutomu Tomita ◽  
Kenji Okajima
Keyword(s):  
Liver Injury ◽  
Rat Model ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion ◽  
Hepatic Tissue ◽  
Therapeutic Effects ◽  
Danaparoid Sodium ◽  
Cgrp Release ◽  
Neuron Activation

SummaryThis study was undertaken to examine the mechanism by which danaparoid sodium (DS), a heparinoid that contains mainly heparan sulfate, prevents reperfusion-induced hepatic damage in a rat model of ischemia/reperfusion (I/R)-induced liver injury. Administration of DS significantly reduced liver injury and inhibited the decrease in hepatic tissue blood flow in rats. DS attenuated hepatic I/R-induced increases in hepatic tissue levels of tumor necrosis factor (TNF) and myeloperoxidase (MPO) in vivo. In contrast, neither monocytic TNF production nor neutrophil activation was inhibited by DS in vitro. DS enhanced I/R-induced increases in levels of calcitonin-gene related peptide (CGRP), a neuropeptide released from sensory neurons, and of 6-ketoprostaglandin (PG) F1α, a stable metabolite of PGI2, in liver tissues. The therapeutic effects of DS were not seen in animals pretreated with capsazepine, an inhibitor of sensory neuron activation. The distribution of heparan sulfate in the perivascular area was significantly increased by DS administration in this rat model. DS significantly increased CGRP release from isolated rat dorsal root ganglion neurons (DRG) in vitro, while DX-9065a, a selective inhibitor of activated factor X, did not. DS enhanced anandamide-induced CGRP release from DRG in vitro. These observations strongly suggested that DS might reduce I/R-induced liver injury in rats by attenuating inflammatory responses. These therapeutic effects of DS might be at least partly explained by its enhancement of sensory neuron activation, leading to the increase the endothelial production of PGI2.

Antithrombin reduces ischemia/reperfusion-induced liver injury in rats by activation of cyclooxygenase-1

2004 ◽  
Vol 92 (09) ◽  
pp. 550-558 ◽  
Author(s):  
Naoaki Harada ◽  
Mitsuhiro Uchiba ◽  
Shigeki Kushimoto ◽  
Hirotaka Isobe ◽  
Kenji Okajima
Keyword(s):  
Liver Injury ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion ◽  
Selective Inhibitor ◽  
Hepatic Tissue ◽  
Tissue Blood Flow ◽  
Mrna Levels ◽  
Tissue Levels ◽  
Cox 2 ◽  
Cox 1

SummaryThis study was conducted to determine which isoform of cyclooxygenase (COX) is more significantly involved in the antithrombin (AT)-induced increase in prostaglandin production in the liver of rats, subjected to hepatic ischemia/reperfusion (I/R). Hepatic tissue levels of 6-keto-PGF1α, a stable metabolite of prostacyclin (PGI2), and PGE2 were transiently increased 1 hour after reperfusion. Thereafter, hepatic PGE2 levels were gradually increased until 6 hours after reperfusion, while hepatic 6-keto-PGF1α levels were decreased to the pre-ischemia levels at 6 hours after reperfusion. AT significantly enhanced increases in hepatic tissue levels of 6-keto-PGF1α and PGE2 seen 1 hour after reperfusion, while it inhibited increases in hepatic PGE2 levels seen 6 h after reperfusion. Neither dansyl-Glu-Gly-Arg-chloromethyl ketone-treated factor Xa (DEGR-Xa), a selective inhibitor of thrombin generation, nor Trp49-modified AT which lacks affinity for heparin, showed any effects on these changes. Pretreatment with indomethacin (IM), a non-selective inhibitor of COX, inhibited AT-induced increases in hepatic tissue levels of 6-keto-PGF1α and PGE2 seen 1 hour after reperfusion, whereas pretreatment with NS-398, a selective inhibitor of COX-2, did not. The increase in hepatic tissue blood flow and inhibition of hepatic inflammatory responses seen in animals given AT were reversed by pretreatment with IM, but were not affected by pretreatment with NS-398. Administration of iloprost, a stable analog of PGI2, and PGE2 produced effects similar to those induced by AT. Increases in hepatic tissue levels of PGE2 6 hours after reperfusion were inhibited by pretreatment with NS-398. Although AT did not affect COX-1 mRNA levels 1 hour after reperfusion, it inhibited the I/R-induced increases in hepatic tissue levels of both PGE2 and COX-2 mRNA 6 hours after reperfusion. These observations strongly suggested that AT might reduce the I/R-induced liver injury by increasing the production of PGI2 and PGE2 through activation of COX-1. Furthermore, since TNF-a is capable of inducing COX-2, inhibition of TNF-a production by AT might inhibit COX-2-mediated PGE2 production. These effects induced by AT might contribute to its anti-inflammatory activity.

Neutrophil elastase contributes to the development of ischemia-reperfusion-induced liver injury by decreasing endothelial production of prostacyclin in rats

2004 ◽  
Vol 287 (6) ◽  
pp. G1116-G1123 ◽  
Author(s):  
Kenji Okajima ◽  
Naoaki Harada ◽  
Mitsuhiro Uchiba ◽  
Masakazu Mori
Keyword(s):  
Blood Flow ◽  
Liver Injury ◽  
Neutrophil Elastase ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Hepatic Tissue ◽  
Tissue Blood Flow ◽  
Protective Effects ◽  
Tissue Levels ◽  
Hepatic Tissue Blood Flow

We previously reported that nitric oxide (NO) derived from endothelial NO synthase (NOS) increased endothelial prostacyclin (PGI2) production in rats subjected to hepatic ischemia-reperfusion (I/R). The present study was undertaken to determine whether neutrophil elastase (NE) decreases endothelial production of PGI2, thereby contributing to the development of I/R-induced liver injury by decreasing hepatic tissue blood flow in rats. Hepatic tissue levels of 6-keto-PGF1α, a stable metabolite of PGI2, were transiently increased and peaked at 1 h after reperfusion, followed by a gradual decrease until 3 h after reperfusion. Sivelestat sodium hydrochloride and L-658,758, two NE inhibitors, reduced I/R-induced liver injury. These substances inhibited the decreases in hepatic tissue levels of 6-keto-PGF1αat 2 and 3 h after reperfusion but did not affect the levels at 1 h after reperfusion. These NE inhibitors significantly increased hepatic tissue blood flow from 1 to 3 h after reperfusion. Both hepatic I/R-induced increases in the accumulation of neutrophils and the microvascular permeability were inhibited by these two NE inhibitors. Protective effects induced by the two NE inhibitors were completely reversed by pretreatment with nitro-l-arginine methyl ester, an inhibitor of NOS, or indomethacin. Administration of iloprost, a stable derivative of PGI2, produced effects similar to those induced by NE inhibitors. These observations strongly suggest that NE might play a critical role in the development of I/R-induced liver injury by decreasing endothelial production of NO and PGI2, leading to a decrease in hepatic tissue blood flow resulting from inhibition of vasodilation and induction of activated neutrophil-induced microvascular injury.

scholarly journals Voltage-gated Na+ currents in human dorsal root ganglion neurons

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Xiulin Zhang ◽  
Birgit T Priest ◽  
Inna Belfer ◽  
Michael S Gold
Keyword(s):  
Sensory Neurons ◽  
Tissue Injury ◽  
Dorsal Root Ganglion Neurons ◽  
Pharmacological Properties ◽  
Pain Mechanisms ◽  
Voltage Gated ◽  
Whole Cell Patch Clamp ◽  
Na Currents ◽  
Ganglion Neurons ◽  
Peripheral Sensory

Available evidence indicates voltage-gated Na+ channels (VGSCs) in peripheral sensory neurons are essential for the pain and hypersensitivity associated with tissue injury. However, our understanding of the biophysical and pharmacological properties of the channels in sensory neurons is largely based on the study of heterologous systems or rodent tissue, despite evidence that both expression systems and species differences influence these properties. Therefore, we sought to determine the extent to which the biophysical and pharmacological properties of VGSCs were comparable in rat and human sensory neurons. Whole cell patch clamp techniques were used to study Na+ currents in acutely dissociated neurons from human and rat. Our results indicate that while the two major current types, generally referred to as tetrodotoxin (TTX)-sensitive and TTX-resistant were qualitatively similar in neurons from rats and humans, there were several differences that have important implications for drug development as well as our understanding of pain mechanisms.

Delta/Notch signaling promotes formation of zebrafish neural crest by repressing Neurogenin 1 function

Development ◽  
2002 ◽  
Vol 129 (11) ◽  
pp. 2639-2648 ◽  
Author(s):  
Robert A. Cornell ◽  
Judith S. Eisen
Keyword(s):  
Dorsal Root Ganglion ◽  
Neural Crest ◽  
Notch Signaling ◽  
Sensory Neurons ◽  
Dorsal Root ◽  
Cell Formation ◽  
Dorsal Root Ganglion Neurons ◽  
Primary Neurons ◽  
Different Types ◽  
Ganglion Neurons

In zebrafish, cells at the lateral edge of the neural plate become Rohon-Beard primary sensory neurons or neural crest. Delta/Notch signaling is required for neural crest formation. ngn1 is expressed in primary neurons; inhibiting Ngn1 activity prevents Rohon-Beard cell formation but not formation of other primary neurons. Reducing Ngn1 activity in embryos lacking Delta/Notch signaling restores neural crest formation, indicating Delta/Notch signaling inhibits neurogenesis without actively promoting neural crest. Ngn1 activity is also required for later development of dorsal root ganglion sensory neurons; however, Rohon-Beard neurons and dorsal root ganglion neurons are not necessarily derived from the same precursor cell. We propose that temporally distinct episodes of Ngn1 activity in the same precursor population specify these two different types of sensory neurons.

Interaction of opioids and membrane potential to modulate Ca2+ channels in rat dorsal root ganglion neurons

1995 ◽  
Vol 73 (5) ◽  
pp. 1793-1798 ◽  
Author(s):  
M. D. Womack ◽  
E. W. McCleskey
Keyword(s):  
Dorsal Root Ganglion ◽  
Sensory Neurons ◽  
Action Potentials ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
High Threshold ◽  
Partial Recovery ◽  
Drg Neurons ◽  
Ganglion Neurons ◽  
Ca2 Channels

1. Using patch-clamp methods, we show that brief prepulses to very positive voltages increase (facilitate) the amplitude of current through Ca2+ channels during a subsequent test pulse in some, but not all, dorsal root ganglion (DRG) sensory neurons. The amplitude of this facilitated current generally increases when the Ca2+ channels are inhibited by activation of the mu-opioid receptor. 2. The facilitated current is blocked by omega-conotoxin GVIA, activates in the range of high-threshold Ca2+ channels, and inactivates at relatively negative holding voltages. Thus facilitated current passes through N-type Ca2+ channels, the same channels that are inhibited by opioids and control neurotransmitter release in sensory neurons. 3. Although maximal facilitation occurs only at unphysiologically high membrane potentials (above +100 mV), some facilitation is seen after prepulses to voltages reached during action potentials. After return to the holding potential, facilitation persists for hundreds of milliseconds, considerably longer than in other neurons. Brief trains of pulses designed to mimic action potentials caused small facilitation (19% of maximal) in a fraction (8 of 24) of opioid-inhibited neurons. 4. We conclude that 1) prepulses to extremely positive voltages can cause partial recovery of Ca2+ channels inhibited by opioids; and 2) small, but detectable, facilitation is also seen after physiological stimulation in some DRG neurons. Facilitation, largely considered a biophysical epiphenomenon because of the extreme voltages used to induce it, appears to be physiologically relevant during opioid inhibition of Ca2+ channels in DRG neurons.

scholarly journals Interferon γ Gene Expression in Sensory Neurons: Evidence for Autocrine Gene Regulation

1997 ◽  
Vol 186 (12) ◽  
pp. 2023-2031 ◽  
Author(s):  
Harald Neumann ◽  
Hannes Schmidt ◽  
Elke Wilharm ◽  
Lüder Behrens ◽  
Hartmut Wekerle
Keyword(s):  
Patch Clamp ◽  
Sensory Neurons ◽  
Nuclear Translocation ◽  
Interferon Γ ◽  
Dorsal Root Ganglion Neurons ◽  
Neuronal Membrane ◽  
Cultured Neurons ◽  
Ifn Γ ◽  
Patch Clamp Electrophysiology ◽  
Ganglion Neurons

We explored expression and possible function of interferon-γ (IFN-γ) in cultured fetal (E15) rat dorsal root ganglion neurons combining whole cell patch-clamp electrophysiology with single cell reverse transcriptase polymerase chain reaction and confocal laser immunocytochemistry. Morphologically, we located IFN-γ protein in the cytoplasm of the neurons in culture as well as in situ during peri- and postnatal development. Transcripts for classic IFN-γ and for its receptor were determined in probes of cytoplasm sampled from individual cultured neurons, which had been identified by patch clamp electrophysiology. In addition, the cultured neurons expressed both chains of the IFN-γ receptor. Locally produced IFN-γ acts back on its cellular source. Phosphorylation and nuclear translocation of the IFN-inducible transcriptional factor STAT1 as well as IFN-γ–dependent expression of major histocompatibility complex class I molecules on the neuronal membrane were noted in untreated cultures. However, both processes were substantially blocked in the presence of antibodies neutralizing IFN-γ. Our findings indicate a role of IFN-γ in autocrine regulation of sensory neurons.

Mitochondrial Modulation of Ca2+-Induced Ca2+-Release in Rat Sensory Neurons

2006 ◽  
Vol 96 (3) ◽  
pp. 1093-1104 ◽  
Author(s):  
Joshua G. Jackson ◽  
Stanley A. Thayer
Keyword(s):  
Plasma Membrane ◽  
Sensory Neurons ◽  
Oscillation Frequency ◽  
Cyclopiazonic Acid ◽  
Cellular Level ◽  
Dorsal Root Ganglion Neurons ◽  
Whole Cell Patch Clamp ◽  
Carbonyl Cyanide ◽  
Synthase Inhibitor ◽  
Ganglion Neurons

Ca2+-induced Ca2+-release (CICR) from ryanodine-sensitive Ca2+ stores provides a mechanism to amplify and propagate a transient increase in intracellular calcium concentration ([Ca2+]i). A subset of rat dorsal root ganglion neurons in culture exhibited regenerative CICR when sensitized by caffeine. [Ca2+]i oscillated in the maintained presence of 5 mM caffeine and 25 mM K+. Here, CICR oscillations were used to study the complex interplay between Ca2+ regulatory mechanisms at the cellular level. Oscillations depended on Ca2+ uptake and release from the endoplasmic reticulum (ER) and Ca2+ influx across the plasma membrane because cyclopiazonic acid, ryanodine, and removal of extracellular Ca2+ terminated oscillations. Increasing caffeine concentration decreased the threshold for action potential-evoked CICR and increased oscillation frequency. Mitochondria regulated CICR by providing ATP and buffering [Ca2+]i. Treatment with the ATP synthase inhibitor, oligomycin B, decreased oscillation frequency. When ATP concentration was held constant by recording in the whole cell patch-clamp configuration, oligomycin no longer affected oscillation frequency. Aerobically derived ATP modulated CICR by regulating the rate of Ca2+ sequestration by the ER Ca2+ pump. Neither CICR threshold nor Ca2+ clearance by the plasma membrane Ca2+ pump were affected by inhibition of aerobic metabolism. Uncoupling electron transport with carbonyl cyanide p-trifluoromethoxy-phenyl-hydrazone or inhibiting mitochondrial Na+/Ca2+ exchange with CGP37157 revealed that mitochondrial buffering of [Ca2+]i slowed oscillation frequency, decreased spike amplitude, and increased spike width. These findings illustrate the interdependence of energy metabolism and Ca2+ signaling that results from the complex interaction between the mitochondrion and the ER in sensory neurons.

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