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排序方式: 共有390条查询结果,搜索用时 15 毫秒
101.
Pain due to peripheral nerve injury or disease is a dynamic process, such that the mechanism that underlies it alters over time. Tramadol has been reported to be analgesic in clinical neuropathic pain, with varying levels of efficacy due to a patient population that has had neuropathic pain for a wide range of time. In order to address and examine the issue, the antinociceptive efficacy of tramadol over time was tested in rats with a chronic constriction injury (CCI) of the left sciatic nerve. Rats developed a robust hind paw hypersensitivity to innocuous mechanical stimulation ipsilateral to CCI surgery. Subcutaneous injection of tramadol in rats two weeks after CCI surgery dose-dependently attenuated mechanical hypersensitivity, which was abolished with the mu-opioid receptor antagonist naloxone but not the alpha(2)-adrenoceptor antagonist yohimbine. Systemic tramadol also attenuated mechanical hypersensitivity four weeks after CCI surgery, but the efficacy significantly diminished at this time point. In addition, the effect of tramadol at this later time point could be reduced with yohimbine as well as naloxone. These data demonstrate that the efficacy of tramadol depends in part on the duration of nerve injury-evoked nociception, and that its antinociceptive mechanism changes over time. Alteration in antinociceptive mechanism over time may explain the inconsistency in efficacy of this and other analgesic drugs in chronic pain patients. 相似文献
102.
103.
There are a number of neurologically active ion channel blocking peptides derived from cone snail venom, such as conantokin-G and ω-conotoxin MVIIA. Conantokin-G inhibits NMDA receptors containing the NR2B subunit whereas ω-conotoxin MVIIA blocks N-type Ca2+ channels. Separately, these peptides induce antinociceptive effects in pre-clinical pain models following intrathecal injection. In the current study, the efficacies of these peptides were determined separately and in combination by intrathecal injection into rats with a spinal nerve ligation, in rats with a spinal cord compression injury and in the formalin test. Separately, both conantokin-G and ω-conotoxin MVIIA dose-dependently attenuated nociceptive responses in all of these models. However, at high antinociceptive doses for both formalin and nerve injury models, ω-conotoxin MVIIA evoked untoward side effects. Using isobolographic analysis, the combination of sub-antinociceptive doses of peptides demonstrated additive antinociception in rats with a nerve ligation and in the formalin test, without apparent adverse side effects. In a model of neuropathic spinal cord injury pain, which is clinically difficult to treat, the combination of conantokin-G and ω-conotoxin MVIIA resulted in robust synergistic antinociception. These data suggest that a combination of these peptides may be analgesic across diverse clinical pains with limited untoward side effects, and particularly potent for reducing spinal cord injury pain. 相似文献
104.
C Hernández E Santamatilde KJ McCreath AM Cervera I Díez D Ortiz-Masiá N Martínez S Calatayud JV Esplugues MD Barrachina 《British journal of pharmacology》2009,156(2):262-272
Background and purpose:
Mucosal microcirculation is compromised during gastric damage induced by non-steroidal anti-inflammatory drugs, such as aspirin. Consequently, oxygen supply to epithelial cells is decreased. The trefoil factor (TFF) peptides are involved in mechanisms of defence and repair in the gastrointestinal tract but their regulation at sites of gastric injury is unknown.Experimental approach:
Hypoxia and expression of TFF genes and peptides were measured in the damaged stomach of aspirin-treated rats. In a human gastric cell line (AGS cells), the effects of hypoxia and of hypoxia inducible factor (HIF)-1 (through transient transfection of HIF-1α siRNA or over-expression of HIF-1α) on TFF gene expression were evaluated.Key results:
Hypoxyprobe immunostaining, up-regulation of TFF2 (1.9-fold) and TFF3 (1.8-fold) and a non-significant increase of TFF1 (1.5-fold) mRNA were observed in the damaged stomach of aspirin-treated rats, compared with control animals. Hypoxia (3% O2, 16 h) induced mRNA for TFF1 (5.8-fold), TTF2 (9.1-fold) and TFF3 (9.3-fold) in AGS cells, an effect mediated by HIF-1, as transient transfection of HIF-1α siRNA reduced the effects of hypoxia. Over-expression of HIF-1α by transfection in non-hypoxic epithelial cells produced a similar pattern of TFF induction to that observed with hypoxia and transactivated a TFF1 reporter construct.Conclusions and implications:
Hypoxia inducible factor-1 mediated the induction of TFF gene expression by hypoxia in gastric epithelial cells. Low oxygen levels and up-regulation of TFF gene expression in the damaged stomach of aspirin-treated rats suggest that hypoxia induced expression of TFF genes at sites of gastric injury. 相似文献105.
N Apostolova LJ Gomez-Sucerquia A Moran A Alvarez A Blas-Garcia JV Esplugues 《British journal of pharmacology》2010,160(8):2069-2084
BACKGROUND AND PURPOSE
Efavirenz (EFV) is widely used in the treatment of HIV-1 infection. Though highly efficient, there is growing concern about EFV-related side effects, the molecular basis of which remains elusive.EXPERIMENTAL APPROACH
In vitro studies were performed to address the effect of clinically relevant concentrations of EFV (10, 25 and 50 µM) on human hepatic cells.KEY RESULTS
Cellular proliferation and viability were reduced in a concentration-dependent manner. Analyses of the cell cycle and several cell death parameters (chromatin condensation, phosphatidylserine exteriorization, mitochondrial proapoptotic protein translocation and caspase activation) revealed that EFV triggered apoptosis via the intrinsic pathway. In addition, EFV directly affected mitochondrial function in a reversible manner, inducing a decrease in mitochondrial membrane potential and an increase in mitochondrial superoxide production, followed by a reduction in cellular glutathione content. The rapidity of these actions rules out any involvement of mitochondrial DNA replication, which, until now, was thought to be the main mechanism of mitochondrial toxicity of antiretroviral drugs. Importantly, we also observed an increase in mitochondrial mass, manifested as an elevated cardiolipin content and enhanced expression of mitochondrial proteins, which was not paralleled by an increase in the mtDNA/nuclear DNA copy number ratio. The toxic effect of EFV was partially reversed by antioxidant pretreatment, which suggests ROS generation is involved in this effect.CONCLUSION AND IMPLICATIONS
Clinically relevant concentrations of EFV were shown to be mitotoxic in human hepatic cells in vitro, which may be pertinent to the understanding of the hepatotoxicity associated with this drug. 相似文献106.
Pre-clinical evidence demonstrates that neuropathic spinal cord injury (SCI) pain is maintained by a number of neurobiological mechanisms, suggesting that treatments directed at several pain-related targets may be more advantageous compared to a treatment focused on a single target. The current study evaluated the efficacy of the non-opiate analgesic acetaminophen, which has several putative analgesic mechanisms, combined with analgesic drugs used to treat neuropathic pain in a rat model of below-level neuropathic SCI pain. Following an acute compression of the mid-thoracic spinal cord, rats exhibited robust hind paw hypersensitivity to innocuous mechanical stimulation. Fifty percent antinociceptive doses of gabapentin, morphine, tramadol or memantine were combined with an ineffective dose of acetaminophen; acetaminophen alone was not antinociceptive. The combination of acetaminophen with either tramadol or memantine resulted in an additive antinociceptive effect. Acetaminophen combined with either morphine or gabapentin, however, resulted in supra-additive (synergistic) efficacy. One of the analgesic mechanisms of acetaminophen is inhibiting the uptake of endocannabinoids from the extracellular space. Pre-treatment with AM251, a cannabinoid-1 receptor (CB1) antagonist, significantly diminished the antinociceptive effect of the acetaminophen + gabapentin combination. Pre-treatment with AM630, a cannabinoid-2 receptor (CB2) antagonist, did not have an effect on this combination. By contrast, both AM251 and AM630 reduced the efficacy of the acetaminophen + morphine combination. None of the active drugs alone were affected by either CB receptor antagonist. The results imply that modulation of the endocannabinoid system in addition to other mechanisms mediate the synergistic antinociceptive effects of acetaminophen combinations. Despite the presence of a cannabinoid mechanism, synergism was not present in all acetaminophen combinations. The combination of currently available drugs may be an appropriate option in ameliorating neuropathic SCI pain if single drug therapy is ineffective. 相似文献
107.
In this work, we studied transgenic glial fibrillary acidic protein-IkappaBalpha-dn mice that selectively inactivate the classical nuclear factor kappaB pathway by overexpressing the inhibitory protein of kappaBalpha in astrocytes, under the control of glial fibrillary acidic protein promoter. We sought to determine if glial nuclear factor kappaB inhibition decreases formalin pain. Formalin testing was carried out on 25-35 g littermate adult male wild-type and transgenic C57Bl/6 mice. Formalin increased spinal cord c-Fos expression and glial fibrillary acidic protein immunostaining in both wild-type and transgenic mice. Transgenic glial fibrillary acidic protein-inhibitory protein of kappaBalpha-dn mice had lower duration of formalin-induced paw-licking behavior. These data support a role of glial nuclear factor kappaB inhibition in reducing pain after peripheral nerve inflammation. 相似文献
108.
体重部分地受大脑或胃肠道合成的肽类激素的调控。Ghrelin前激素原含117个氨基酸残基,经翻译后裂解作用形成Ghrelin,由28个氨基酸组成。我们检索基因库,与另外11种哺乳动物进行Ghrelin前激素原的序列比较,除了已知的Ghrelin信号肽,我们还确定了另一保守区,侧链含有转化酶裂解部位,编码一种23个氨基酸的肽链,其C端侧翼有保守的甘氨酸残基,可能经酰胺化作用。我们称此Ghrelin相关肽为肥胖抑素(Obestatin)。 相似文献
109.
110.
Adrenal medullary transplants reduce formalin-evoked c-fos expression in the rat spinal cord 总被引:4,自引:0,他引:4
Previous studies have indicated that adrenal medullary chromaffin cells transplanted into the spinal subarachnoid space can alleviate pain behaviors in several animal models. The goal of this study was to assess whether decreased activation of spinal dorsal horn neurons responsive to nociceptive stimuli may contribute to these antinociceptive effects. In order to address this, expression of neural activity marker c-fos in response to intraplantar formalin was evaluated in animals with intrathecal adrenal medullary or control striated muscle transplants. Adrenal medullary transplants significantly attenuated formalin-induced flinching behaviors in both acute and tonic phases of the formalin response, in comparison with control transplanted animals. Fos-like-immunoreactive (Fos-LI) cell numbers were markedly reduced in the dorsal horns of animals with adrenal medullary transplants in comparison to robust Fos-LI expression in control transplanted animals. This reduction was observed in both superficial and deep laminae of the dorsal horn, but the magnitude of the decrease was greatest in lamina V. Similar to reports using other antinociceptive treatments, some residual c-fos expression was observed, particularly in laminae I-II, in animals with adrenal medullary transplants. The results of these studies suggest that adrenal medullary transplants produce antinociception in part by inhibiting spinal dorsal horn neuronal activation in response to noxious stimuli. 相似文献