Inflammation-reactive astrocytes can be restored with a three drug combination

2014 ◽  
Vol 5 (3) ◽  
pp. 209-209
Author(s):  
E. Hansson ◽  
L. Block ◽  
U. Björklund ◽  
B. Biber

Abstract Aims In inflammation-reactive astrocytes the cell parameters, Ca2+ signalling, Na+ transporters, cytoskeleton, and release of proinflammatory cytokines are affected. We want to re-establish these parameters with agents, which might have a potential to restore the cells back to a normal non-inflammatory level. Methods Astrocytes in primary cultures were incubated with lipopolysaccharide (LPS) (10 ng/ml) for 24 h to become inflammation-reactive. Different parameters were analysed to verify this inflammation: Ca2+ signalling, Na+/K+-ATPase expression, actin filament organization, and interleukin-1beta release (IL-1β). Results We have used an opioid agonist, endomorphin-1, that stimulates the Gi/o protein of the μ-opioid receptor, an opioid antagonist, naloxone, that inhibits the Gs protein of the μ-opioid receptor in ultralow concentrations, and an anti-epileptic agent, levetiracetam, that counteracts the release of IL-1β. The combination of these three agents managed to activate the Gi/o protein and Na+/K+-ATPase activity, inhibit the Gs protein, and decrease the release of IL-1β. The disorganized actin filaments were restored. Conclusions The findings that the important cell parameters in astrocytes were restored back to their normal non-inflammatory state after the cells were treated with the inflammatory agent LPS could be of clinical significance. It may be useful for the treatment of neuroinflammation and also maybe of long-term pain. The astrocyte networks play a significant role and therefore a well-working intercellular Ca2+ signalling is of utmost importance. Significance These findings put new potential drug regimens towards treatment of neuroinflammation and long-term pain into focus.

2009 ◽  
Vol 75 (4) ◽  
pp. 744-750 ◽  
Author(s):  
Qifang Wu ◽  
Lei Zhang ◽  
Ping-Yee Law ◽  
Li-Na Wei ◽  
Horace H. Loh

1993 ◽  
Vol 113 (2) ◽  
pp. 167-171 ◽  
Author(s):  
Junzo Kamei ◽  
Naoya Kawashima ◽  
Yuriko Iwamoto ◽  
Tsutomu Suzuki ◽  
Hiroshi Nagase ◽  
...  

2003 ◽  
Vol 285 (6) ◽  
pp. R1287-R1304 ◽  
Author(s):  
Peter M. Lalley

μ-Opioid receptor agonists depress tidal volume, decrease chest wall compliance, and increase upper airway resistance. In this study, potential neuronal sites and mechanisms responsible for the disturbances were investigated, dose-response relationships were established, and it was determined whether general anesthesia plays a role. Effects of μ-opioid agonists on membrane properties and discharges of respiratory bulbospinal, vagal, and propriobulbar neurons and phrenic nerve activity were measured in pentobarbital-anesthetized and unanesthetized decerebrate cats. In all types of respiratory neurons tested, threshold intravenous doses of the μ-opioid agonist fentanyl slowed discharge frequency and prolonged duration without altering peak discharge intensity. Larger doses postsynaptically depressed discharges of inspiratory bulbospinal and inspiratory propriobulbar neurons that might account for depression of tidal volume. Iontophoresis of the μ-opioid agonist DAMGO also depressed the intensity of inspiratory bulbospinal neuron discharges. Fentanyl given intravenously prolonged discharges leading to tonic firing of bulbospinal expiratory neurons in association with reduced hyperpolarizing synaptic drive potentials, perhaps explaining decreased inspiratory phase chest wall compliance. Lowest effective doses of fentanyl had similar effects on vagal postinspiratory (laryngeal adductor) motoneurons, whereas in vagal laryngeal abductor and pharyngeal constrictor motoneurons, depression of depolarizing synaptic drive potentials led to sparse, very-low-frequency discharges. Such effects on three types of vagal motoneurons might explain tonic vocal fold closure and pharyngeal obstruction of airflow. Measurements of membrane potential and input resistance suggest the effects on bulbospinal Aug-E neurons and vagal motoneurons are mediated presynaptically. Opioid effects on the respiratory neurons were similar in anesthetized and decerebrate preparations.


2021 ◽  
Author(s):  
Katy J Sutcliffe ◽  
Robin A Corey ◽  
Steven J Charlton ◽  
Richard B Sessions ◽  
Graeme Henderson ◽  
...  

AbstractOverdose deaths from synthetic opioids, such as fentanyl, have reached epidemic proportions in the USA and are increasing worldwide. Fentanyl is a potent opioid agonist, that is less well reversed by naloxone than morphine. Due to fentanyl’s high lipophilicity and elongated structure we hypothesised that its unusual pharmacology may be explained by a novel binding mode to the μ-opioid receptor (MOPr).By employing coarse-grained molecular dynamics simulations and free energy calculations, we determined the routes by which fentanyl and morphine access the orthosteric pocket of MOPr.Morphine accesses MOPr via the aqueous pathway; first binding to an extracellular vestibule, then diffusing into the orthosteric pocket. In contrast, fentanyl takes a novel route; first partitioning into the membrane, before accessing the orthosteric site by diffusing through a ligand-induced gap between the transmembrane helices.This novel lipophilic route may explain the high potency and lower susceptibility of fentanyl to reversal by naloxone.


2000 ◽  
Vol 39 (6) ◽  
pp. 952-960 ◽  
Author(s):  
Henry Matthies ◽  
Helmut Schroeder ◽  
Axel Becker ◽  
Horace Loh ◽  
Volker Höllt ◽  
...  

2021 ◽  
pp. 174480692098844
Author(s):  
Chinwe Nwaneshiudu ◽  
Xiao-You Shi ◽  
Peyman Sahbaie ◽  
J. David Clark

Recent reports suggest pain from surgical injury may influence the risks associated with exposure to opioids. In mice, hind-paw incision attenuates morphine-primed reinstatement due to kappa opioid receptor activation by dynorphin. In this focused group of studies, we examined the hypotheses that kappa-opioid receptor activation in the nucleus accumbens mediates attenuated drug- primed reinstatement after incisional surgery, and the G-protein biased mu-opioid agonist, oliceridine, leads to less priming of the dynorphin effect in comparison to morphine. To address these hypotheses, adult C57BL/6 male mice underwent intracranial cannulation for administration of the selective kappa-opioid antagonist norBNI directly into the nucleus accumbens. After recovery, they were conditioned with morphine or oliceridine after hind-paw incisional injury, then underwent extinction followed by opioid-primed reinstatement. Intra-accumbal administration of norBNI was carried out prior to testing. The nucleus accumbens and medial prefrontal cortex were extracted and analyzed for expression of prodynorphin. We observed that animals conditioned with morphine in the setting of incisional injury demonstrated blunted responses to opioid-primed reinstatement, and that the blunted responses were reversed with intra-accumbal norBNI administration. Persistently elevated levels of prodynorphin expression in the medial prefrontal cortex and nucleus accumbens were observed in the incised morphine-treated animals. However, both behavioral and molecular changes were absent in animals with incisional injury conditioned with oliceridine. These findings suggest a role for prodynorphin expression in the nucleus accumbens with exposure to morphine after surgery that may protect individuals from relapse not shared with biased mu- opioid receptor agonists.


Author(s):  
Darius A. Rastegar

Opioids are a class of drugs that include heroin and prescription pain relievers that produce analgesia and euphoria. More than 2 million Americans have an opioid use disorder. Acute effects include analgesia, respiratory depression, miosis, and euphoria. Overdose is a serious complication of opioid use, characterized by depressed level of consciousness and respiratory depression. It can be treated with naloxone. Withdrawal symptoms include dysphoria, yawning, tearing, diarrhea, cramps, nausea, and piloerection. Buprenorphine, methadone, clonidine, and lofexidine can be used to ameliorate the symptoms of withdrawal. However, supervised withdrawal alone rarely leads to long-term abstinence. There are a number of psychosocial treatments, including self-help groups, outpatient therapy, and residential treatment; the data on their effectiveness are limited. Pharmacotherapy with an opioid agonist (methadone or buprenorphine) is the most effective treatment. Long-acting injectable naltrexone, an opioid antagonist, is also effective, but it is more difficult to initiate.


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