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S Mohammad Ahmadi Soleimani, Hossein Azizi, Narges Pachenari, Javad Mirnajafi-Zadeh, Saeed Semnanian
Opioids have always been used in clinical practice for pain management. However, development of tolerance to their effects following long term administration, seriously restricts further clinical use of these drugs. In this regard, μ-opioid receptor (MOR) desensitization, as an initial step in development of opioid tolerance, is of particular significance. Previous studies support the involvement of orexinergic system in development of opioid tolerance. Locus coeruleus (LC) nucleus has been shown to modulate pain and development of tolerance...
March 23, 2017: Neuropeptides
B Sayyaf Dezfuli, J A DePasquale, G Castaldelli, L Giari, G Bosi
Immunohistochemical, immunofluorescence and ultrastructural studies were conducted on a sub-population of 20 wels catfish Silurus glanis from a tributary of the River Po (Northern Italy). Fish were examined for the presence of ecto- and endo-parasites; in the intestine of 5 fish, 11 specimens of cestode Glanitaenia osculata were noted and was the only helminth species encountered. The architecture of intestine and its cellular features were nearly identical in either the uninfected S. glanis or in those harboring G...
May 2017: Fish & Shellfish Immunology
Saurabh Shukla, Zahra Shamsi, Alexander S Moffett, Balaji Selvam, Diwakar Shukla
Hidden Markov models (HMMs) provide a framework to analyze large trajectories of biomolecular simulation datasets. HMMs decompose the conformational space of a biological molecule into finite number of states that interconvert among each other with certain rates. HMMs simplify long timescale trajectories for human comprehension, and allow comparison of simulations with experimental data. In this chapter, we provide an overview of building HMMs for analyzing bimolecular simulation datasets. We demonstrate the procedure for building a Hidden Markov model for Met-enkephalin peptide simulation dataset and compare the timescales of the process...
2017: Methods in Molecular Biology
Antonieta Cote-Vélez, Anabel Martínez Báez, Leticia Lezama, Rosa María Uribe, Patricia Joseph-Bravo, Jean-Louis Charli
In the paraventricular nucleus of the mammalian hypothalamus, hypophysiotropic thyrotropin releasing hormone (TRH) neurons integrate metabolic information and control the activity of the thyroid axis. Additional populations of TRH neurons reside in various hypothalamic areas, with poorly defined connections and functions, albeit there is evidence that some may be related to energy balance. To establish extracellular modulators of TRH hypothalamic neurons activity, we performed a screen of neurotransmitters effects in hypothalamic cultures...
February 2, 2017: Neuropeptides
MinJun Lee, Jeseong Yoon, Soonmin Jang, Seokmin Shin
Although the replica exchange methods (REMs) were developed as efficient conformational sampling methods for bio-molecular simulations, their application to very large bio-systems is somewhat limited. We propose a new replica exchange scheme (Tq-REM) created by combining the conventional temperature-REM (T-REM) and one of the Hamiltonian-REMs, q-REM, using the effective potential with reduced barriers. In the proposed Tq-REM scheme, high temperature replicas in T-REM are substituted with q-replicas. This combined scheme is expected to exploit advantages of the T-REM and q-REM resulting in improved sampling efficiency while minimizing the drawbacks of both approaches...
February 6, 2017: Physical Chemistry Chemical Physics: PCCP
Ashkan Fakharzadeh, Mahmoud Moradi
We present a Riemannian formalism for effective diffusion of biomolecules in collective variable spaces that provides a robust framework for conformational free energy calculation methods. Unlike their Euclidean counterparts, the Riemannian potential of mean force (PMF) and minimum free energy path (MFEP) are invariant under coordinate transformations. The presented formalism can be readily employed to modify the collective variable based enhanced sampling techniques, such as umbrella sampling (US) commonly used in biomolecular simulations, to take into account the role of intrinsic geometry of collective variable space...
December 15, 2016: Journal of Physical Chemistry Letters
K Palus, L Chrobok, M Kepczynski, M H Lewandowski
The intergeniculate leaflet (IGL) is a flat thalamic nucleus implicated in the modulation of circadian rhythmicity. In rat, two main GABAergic subpopulations can be distinguished in the IGL: neurons synthesizing neuropeptide Y (NPY), which directly innervates the suprachiasmatic nuclei, and enkephalinergic cells, which connect contralaterally located leaflets. The aim of this study was to evaluate possible effects of inner IGL neurotransmitters on the spontaneous and synaptic activity of IGL neurons. The data presented in this article provide evidence that enkephalin, and not NPY, could act upon the majority of IGL neurons...
December 2, 2016: Neuroscience
James Lincoff, Sukanya Sasmal, Teresa Head-Gordon
We compare two standard replica exchange methods using temperature and dielectric constant as the scaling variables for independent replicas against two new corresponding enhanced sampling methods based on non-equilibrium statistical cooling (temperature) or descreening (dielectric). We test the four methods on a rough 1D potential as well as for alanine dipeptide in water, for which their relatively small phase space allows for the ability to define quantitative convergence metrics. We show that both dielectric methods are inferior to the temperature enhanced sampling methods, and in turn show that temperature cool walking (TCW) systematically outperforms the standard temperature replica exchange (TREx) method...
November 7, 2016: Journal of Chemical Physics
Mohammad-Ali Yazdani Abyaneh, Peter Engel, Andrzej Slominski, Bruce Ragsdale, Richard Agag, Daniel Cramer, J Andrew Carlson
BACKGROUND: Giant basal cell carcinomas (GBCCs), (BCC ≥ 5 cm), are often painless, destructive tumors resulting from poorly understood patient neglect. OBJECTIVES: To elucidate etiopathogenic factors distinguishing GBCC from basal cell carcinoma (BCC) and identify predictors for disease-specific death (DSD). METHODS: Case-control study examining clinicopathologic and neuroactive factors (β-endorphin, met-enkephalin, serotonin, adrenocorticotropic hormone, and neurofilament expression) in GBCC and BCC...
March 2017: American Journal of Dermatopathology
Tyler A Johnson, Laura Milan-Lobo, Tao Che, Madeline Ferwerda, Eptisam Lambu, Nicole L McIntosh, Fei Li, Li He, Nicholas Lorig-Roach, Phillip Crews, Jennifer L Whistler
Opioid therapeutics are excellent analgesics, whose utility is compromised by dependence. Morphine (1) and its clinically relevant derivatives such as OxyContin (2), Vicodin (3), and Dilaudid (4) are "biased" agonists at the μ opioid receptor (OR), wherein they engage G protein signaling but poorly engage β-arrestin and the endocytic machinery. In contrast, endorphins, the endogenous peptide agonists for ORs, are potent analgesics, show reduced liability for tolerance and dependence, and engage both G protein and β-arrestin pathways as "balanced" agonists...
March 15, 2017: ACS Chemical Neuroscience
Maria Pannell, Dominika Labuz, Melih Ö Celik, Jacqueline Keye, Arvind Batra, Britta Siegmund, Halina Machelska
BACKGROUND: During the inflammation which occurs following nerve damage, macrophages are recruited to the site of injury. Phenotypic diversity is a hallmark of the macrophage lineage and includes pro-inflammatory M1 and anti-inflammatory M2 populations. Our aim in this study was to investigate the ability of polarized M0, M1, and M2 macrophages to secrete opioid peptides and to examine their relative contribution to the modulation of neuropathic pain. METHODS: Mouse bone marrow-derived cells were cultured as unstimulated M0 macrophages or were stimulated into an M1 phenotype using lipopolysaccharide and interferon-γ or into an M2 phenotype using interleukin-4...
October 7, 2016: Journal of Neuroinflammation
Dominika Labuz, Melih Ö Celik, Andreas Zimmer, Halina Machelska
Neuropathic pain often results from peripheral nerve damage, which can involve immune response. Local leukocyte-derived opioid peptides or exogenous opioid agonists inhibit neuropathy-induced mechanical hypersensitivity in animal models. Since neuropathic pain can also be augmented by heat, in this study we investigated the role of opioids in the modulation of neuropathy-evoked heat hypersensitivity. We used a chronic constriction injury of the sciatic nerve in wild-type and opioid peptide-knockout mice, and tested opioid effects in heat and mechanical hypersensitivity using Hargreaves and von Frey tests, respectively...
2016: Scientific Reports
S Corner, T Walsh, L Padilla, A MacNeill, M Wallig, M Kiupel, K Terio
Clouded leopards in North American zoological institutions have a high frequency of pheochromocytomas and were identified in 32 of 70 (45%) animals necropsied. Archival sections of adrenal gland from 20 adult clouded leopards with unilateral or bilateral pheochromocytomas collected between 1984 and 2011 were examined by light microscopy and immunohistochemistry, and case demographics were reviewed. Affected leopards were older than 10 years of age (mean, 16 years; range, 11-19 years), and males were overrepresented (12 males, 8 females)...
March 2017: Veterinary Pathology
Juan A Estrada, Mathew A Barlow, Darice Yoshishige, Arthur G Williams, H Fred Downey, Robert T Mallet, James L Caffrey
BACKGROUND: Intermittent hypoxia training (IHT) produces robust myocardial protection against ischemia-reperfusion induced infarction and arrhythmias. Blockade of this cardioprotection by antagonism of either β1-adrenergic or δ-opioid receptors (δ-OR) suggests autonomic and/or opioidergic adaptations. PURPOSE: To test the hypothesis that IHT shifts cardiac autonomic balance toward greater cholinergic and opioidergic influence. METHODS: Mongrel dogs completed 20d IHT, non-hypoxic sham training, or IHT with the δ-OR antagonist naltrindole (200μg/kgsc)...
July 2016: Autonomic Neuroscience: Basic & Clinical
Riaz A Khan
The Met-enkephalin, Tyr-Gly-Gly-Phe-Met, was synthesized by the solution phase synthesis (SPS) methodology employing -OBzl group as carboxyls protection while the t-Boc groups were employed for the N-terminal α-amines protection for the majority of the amino acids of the pentapeptide sequence. The L-methionine (L-Met) amino acid was used as PTSA.Met-OBzl obtained from the simultaneous protection of the α-amino, and carboxyl group with para-toluene sulfonic acid (PTSA) and as benzyl alcohol ester respectively, in a C-terminal start of the 2+2+1 fragments condensation convergent synthetic approach...
July 19, 2016: Chemical Biology & Drug Design
Roza Szweda, Barbara Trzebicka, Andrzej Dworak, Lukasz Otulakowski, Dominik Kosowski, Justyna Hertlein, Emi Haladjova, Stanislav Rangelov, Dawid Szweda
This study describes a novel approach to polymeric nanocarriers of the therapeutic peptide met-enkephalin based on the aggregation of thermoresponsive polymers. Thermoresponsive bioconjugate poly((di(ethylene glycol) monomethyl ether methacrylate)-ran-(oligo(ethylene glycol) monomethyl ether methacrylate) is synthesized by AGET ATRP using modified met-enkephalin as a macroinitiator. The abrupt heating of bioconjugate water solution leads to the self-assembly of bioconjugate chains and the formation of mesoglobules of controlled sizes...
August 8, 2016: Biomacromolecules
L M A Colgin, D J Schwahn, F Castillo-Alcala, M Kiupel, A D Lewis
Pheochromocytoma, a rarely reported adrenal gland neoplasm in Old World primates, was diagnosed in 5 rhesus macaques (Macaca mulatta) and 2 African green monkeys (Chlorocebus aethiops) from 3 research institutions. Age and sex were available for 6 primates. Two males and 4 females were affected, ranging in age from 9 to 31 years. All neoplasms were unilateral and, in the cases reporting the affected gland, 4 involved the right adrenal gland and 2 involved the left. Diagnosis was established by characteristic histologic features...
November 2016: Veterinary Pathology
Zigor Aira, Teresa Barrenetxea, Itsaso Buesa, Gontzal García Del Caño, Jon Jatsu Azkue
UNLABELLED: The current study reports on a synaptic mechanism through which D1-like receptors (D1LRs) modulate spinal nociception and plasticity by regulating activation of the μ-opioid receptor (MOR).D1LR stimulation with agonist SKF 38393 concentration-dependently depressed C-fiber-evoked potentials in rats receiving spinal nerve ligation (SNL), but not in uninjured rats. Depression was prevented by MOR- but not GABA-receptor blockade. Neurons expressing the D1 subtype were immunopositive for met-enkephalin and vesicular glutamate transporter VGLUT2, but not for GABAergic marker vGAT...
May 18, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Melih Ö Celik, Dominika Labuz, Karen Henning, Melanie Busch-Dienstfertig, Claire Gaveriaux-Ruff, Brigitte L Kieffer, Andreas Zimmer, Halina Machelska
Opioids are the most powerful analgesics. As pain is driven by sensory transmission and opioid receptors couple to inhibitory G proteins, according to the classical concept, opioids alleviate pain by activating receptors on neurons and blocking the release of excitatory mediators (e.g., substance P). Here we show that analgesia can be mediated by opioid receptors in immune cells. We propose that activation of leukocyte opioid receptors leads to the secretion of opioid peptides Met-enkephalin, β-endorphin and dynorphin A (1-17), which subsequently act at local neuronal receptors, to relieve pain...
October 2016: Brain, Behavior, and Immunity
Ryuhei Harada, Yu Takano, Yasuteru Shigeta
The TaBoo SeArch (TBSA) algorithm [ Harada et al. J. Comput. Chem. 2015 , 36 , 763 - 772 and Harada et al. Chem. Phys. Lett. 2015 , 630 , 68 - 75 ] was recently proposed as an enhanced conformational sampling method for reproducing biologically relevant rare events of a given protein. In TBSA, an inverse histogram of the original distribution, mapped onto a set of reaction coordinates, is constructed from trajectories obtained by multiple short-time molecular dynamics (MD) simulations. Rarely occurring states of a given protein are statistically selected as new initial states based on the inverse histogram, and resampling is performed by restarting the MD simulations from the new initial states to promote the conformational transition...
May 10, 2016: Journal of Chemical Theory and Computation
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