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Junko Kimura-Kuroda, Yasumasa Nishito, Hiroko Yanagisawa, Yoichiro Kuroda, Yukari Komuta, Hitoshi Kawano, Masaharu Hayashi
Neonicotinoids are considered safe because of their low affinities to mammalian nicotinic acetylcholine receptors (nAChRs) relative to insect nAChRs. However, because of importance of nAChRs in mammalian brain development, there remains a need to establish the safety of chronic neonicotinoid exposures with regards to children's health. Here we examined the effects of longterm (14 days) and low dose (1 μM) exposure of neuron-enriched cultures from neonatal rat cerebellum to nicotine and two neonicotinoids: acetamiprid and imidacloprid...
October 4, 2016: International Journal of Environmental Research and Public Health
Wenming Zhang, Caleb W Holyoke, James Barry, Robert M Leighty, Daniel Cordova, Daniel R Vincent, Kenneth A Hughes, My-Hanh T Tong, Stephen F McCann, Ming Xu, Twyla A Briddell, Thomas F Pahutski, George P Lahm
A novel class of mesoionic pyrido[1,2-a]pyrimidinones has been discovered with exceptional insecticidal activity controlling a number of insect species, particularly hemiptera and lepidoptera. Mode-of-action studies showed that they act on nicotinic acetylcholine receptors (nAChRs) primarily as inhibitors. Here we report the discovery, evolution, and preparation of this class of chemistry. Our efforts in structure-activity relationship elucidation and biological activity evaluation are also presented.
October 13, 2016: Bioorganic & Medicinal Chemistry Letters
Jiradanai Sarasamkan, Matthias Scheunemann, Nattayaporn Apaijai, Siripong Palee, Warisara Parichatikanond, Kuntarat Arunrungvichian, Steffen Fischer, Siriporn Chattipakorn, Winnie Deuther-Conrad, Gerrit Schüürmann, Peter Brust, Opa Vajragupta
The novel quinuclidine anti-1,2,3-triazole derivatives T1-T6 were designed based on the structure of QND8. The binding studies revealed that the stereochemistry at the C3 position of the quinuclidine scaffold plays an important role in the nAChR subtype selectivity. Whereas the (R)-enantiomers are selective to α7 over α4β2 (by factors of 44-225) and to a smaller degree over α3β4 (3-33), their (S)-counterparts prefer α3β4 over α4β2 (62-237) as well as over α7 (5-294). The (R)-derivatives were highly selective to α7 over α3β4 subtypes compared to (RS)- and (R)-QND8...
October 13, 2016: ACS Medicinal Chemistry Letters
Mathias Kranz, Bernhard Sattler, Solveig Tiepolt, Stephan Wilke, Winnie Deuther-Conrad, Cornelius K Donat, Steffen Fischer, Marianne Patt, Andreas Schildan, Jörg Patt, René Smits, Alexander Hoepping, Jörg Steinbach, Osama Sabri, Peter Brust
BACKGROUND: Both enantiomers of [(18)F]flubatine are new radioligands for neuroimaging of α4β2 nicotinic acetylcholine receptors with positron emission tomography (PET) exhibiting promising pharmacokinetics which makes them attractive for different clinical questions. In a previous preclinical study, the main advantage of (+)-[(18)F]flubatine compared to (-)-[(18)F]flubatine was its higher binding affinity suggesting that (+)-[(18)F]flubatine might be able to detect also slight reductions of α4β2 nAChRs and could be more sensitive than (-)-[(18)F]flubatine in early stages of Alzheimer's disease...
December 2016: EJNMMI Physics
Shih-Hsin Tu, Yin-Ching Lin, Chi-Cheng Huang, Po-Sheng Yang, Hui-Wen Chang, Chien-Hsi Chang, Chih-Hsiung Wu, Li-Ching Chen, Yuan-Soon Ho
We previously demonstrated that the activation of α9-nicotinic acetylcholine receptor (α9-nAchR) signaling by smoking promotes breast cancer formation. To investigate the downstream signaling molecules involved in α9-nAChR-induced breast tumorigenesis, we used real-time polymerase chain reactions and Western blotting to assess expression of protein phosphatase Mg2+/Mn2+ dependent 1F (PPM1F), a Ser/Thr protein phosphatase, in human breast cancer samples (n=167). Additionally, stable PPM1F-knockdown and -overexpressing cell lines were established to evaluate the function of PPM1F...
October 18, 2016: Oncotarget
Kaori Yamada-Nomoto, Osamu Yoshino, Ikumi Akiyama, Akemi Ushijima, Yosuke Ono, Tomoko Shima, Akitoshi Nakashima, Shusaku Hayashi, Makoto Kadowaki, Yutaka Osuga, Shigeru Saito
OBJECTIVE: We investigated α-7 nAchR expression in human peritoneal macrophages and examined whether activation of nAchR might be a new therapy for endometriosis. MATERIALS AND METHODS: Human peritoneal fluid mononuclear cells (PFMC) were stimulated with lipopolysaccharide (LPS) in the presence of α-7 nAChR agonists. In a murine endometriosis model, α-7 nAChR modulators were administered. RESULTS: Human PFMC expressed α-7 nAChR at the mRNA and protein levels...
October 21, 2016: American Journal of Reproductive Immunology: AJRI
(no author information available yet)
[This corrects the article DOI: 10.1371/journal.pone.0161154.].
2016: PloS One
Madeleine Berger, Alin Mirel Puinean, Emma Randall, Christoph T Zimmer, Wellington M Silva, Pablo Bielza, Linda M Field, David Hughes, Ian Mellor, Keywan Hassani-Pak, Herbert A A Siqueira, Martin S Williamson, Chris Bass
Many genes increase coding capacity by alternate exon usage. The gene encoding the insect nicotinic acetylcholine receptor (nAChR) α6 subunit, target of the bio-insecticide spinosad, is one example of this and expands protein diversity via alternative splicing of mutually exclusive exons. Here we show that spinosad resistance in the tomato leafminer, Tuta absoluta is associated with aberrant regulation of splicing of Taα6 resulting in a novel form of insecticide resistance mediated by exon skipping. Sequencing of the α6 subunit cDNA from spinosad selected and unselected strains of T...
October 17, 2016: Molecular Ecology
Hussein I El-Subbagh, Adel S El-Azab, Ghada S Hassan, Shahenda M El-Messery, Alaa A-M Abdel-Aziz, Kamal E H El-Taher
The synthesis, biological evaluation and molecular modeling study of 6,7-dihydro-[1,3,4] thiadiazolo[3,2-a][1,3]diazepine analogues as new class of neuromuscular blocking agents are described. The new compounds act via competitive mechanism with ACh which could be reversed by the anticholinesterase - Physostigmine. Compounds GS-53 (30) and AAH1 (33) induced dose-dependent neuromuscular blockade with onset time of 3 and 10 min, ED50 0.15 and 0.36 mmol/kg i.p., respectively, in rats. Compound 30 proved to be as twice as potent as 33 with rapid onset and shorter duration (P < 0...
September 30, 2016: European Journal of Medicinal Chemistry
Josephine R Tarren, Selena E Bartlett
While the co-morbidity of alcohol (ethanol) and tobacco (nicotine) dependence is well described, the processes that underpin this strong connection are still under debate. With the increasing popularity of electronic cigarettes (e-cigarettes), it is now becoming more important to look to the neurobiological mechanisms involving alcohol and nicotine interactions to effectively treat a new generation of co-dependent individuals. Researchers have already recognized that the neuropathology produced by the combination of nicotine and ethanol is likely to produce an addictive nature very different to that of either one alone, and are employing a mixture of pre-clinical techniques to establish and investigate every stage in the development of both nicotine and ethanol-seeking behaviors...
October 14, 2016: American Journal of Drug and Alcohol Abuse
Bo Lin, Shihua Xiang, Mengsen Li
Nicotinic acetylcholine receptors (nAChRs) are targets for developing new drugs to treat severe pain, nicotine addiction, Alzheimer disease, epilepsy, etc. α-Conotoxins are biologically and chemically diverse. With 12-19 residues and two disulfides, they can be specifically selected for different nAChRs. Acetylcholine-binding proteins from Aplysia californica (Ac-AChBP) are homologous to the ligand-binding domains of nAChRs and pharmacologically similar. X-ray structures of the α-conotoxin in complex with Ac-AChBP in addition to computer modeling have helped to determine the binding site of the important residues of α-conotoxin and its affinity for nAChR subtypes...
October 11, 2016: Marine Drugs
Pauline W Ondachi, Ana H Castro, Benjamin Sherman, Charles W Luetje, M Imad Damaj, Samuel Wayne Mascarella, Hernán A Navarro, Frank Ivy Carroll
The synthesis, nAChR in vitro and in vivo pharmacological properties of 2'-fluoro-3'-(substituted thiophenyl)deschloroepibatidine analogues (5a-f, 6a-d, and 7a-c) are presented herein. All had subnanomolar affinity at α4β2*-nAChRs. Contrary to lead structure epibatidine, a potent nAChR agonist, all were potent α4β2- and α3β4-AChR antagonists in an in vitro functional assay. In vivo, the compounds were also nAChR antagonists with various degrees of agonist activity. Compounds 5e, 5f, 6a, 6c, 6d, and 7c had no agonist effects in the tail-flick, hot-plate, hypothermia, or spontaneous activity tests whereas 5a-d, 7a and 7b did not have agonist activity in the tail-flick and hot-plate tests but like varenicline, were agonists in the hypothermia and spontaneous activity tests...
October 11, 2016: ACS Chemical Neuroscience
Syeda Mehpara Farhat, Touqeer Ahmed
Alzheimer&#039;s disease, a neurodegenerative disorder, is characterized by accumulation of amyloid beta (Aβ) plaques, neurofibrillary tangles and loss of cholinergic neurons. The localization of Aβ plaques particularly in the cholinergic neuron-rich areas has led to the discovery that Aβ binds to α7 nicotinic acetylcholine receptors (nAChRs) with very high affinity. This discovery has led to extensive exploration of the possible outcomes of this binding, ranging from the subcellular signaling pathways to its effects on behavioral and cognitive functions...
October 5, 2016: Current Drug Targets
Barbara J Morley, Anna Lysakowski, Sarath Vijayakumar, Deanna Menapace, Timothy A Jones
Little is known about the function of the cholinergic efferents innervating peripheral vestibular hair cells. We measured vestibular sensory evoked potentials (VsEPs) in α9 knockout mice, α10 knockout mice, α7 knockout mice, α9/10 and α7/9 double knockouts, and wild type controls. We also studied the morphology and ultrastructure of efferent terminals on vestibular hair cells in α9, α10 and α9/10 knockouts. Both type I and type ll vestibular hair cells express the α9 and α10 subunits. The efferent boutons on vestibular cells in α9, α10 and α9/10 knockouts appeared normal, but a quantitative analysis was not performed...
October 7, 2016: Journal of Comparative Neurology
Agnieszka Potasiewicz, Małgorzata Hołuj, Tomasz Kos, Piotr Popik, Hugo R Arias, Agnieszka Nikiforuk
The cognitive impairments and negative symptoms experienced by schizophrenia patients still await effective treatment. Alpha7 nicotinic acetylcholine receptors (α7 nAChRs) have gain considerable attention in this regard. It has been recently proposed that positive allosteric modulators (PAMs) of α7 nAChRs may represent an alternative strategy to that based on orthosteric agonists. The aim of the present study is to evaluate the efficacy of PAM-2 (3-furan-2-yl-N-p-tolyl-acrylamide) against cognitive deficits and negative-like symptoms in a rat model of schizophrenia based on administration of ketamine, a NMDAR antagonist...
October 4, 2016: Neuropharmacology
Lorenzo Di Cesare Mannelli, Laura Micheli, Mario Maresca, Giancarlo Cravotto, Maria Bellumori, Marzia Innocenti, Nadia Mulinacci, Carla Ghelardini
Traditional uses and current results highlight the neuroprotective properties of Rosmarinus officinalis L. The compelling need for novel strategies able to relieve neuropathic pain encouraged us to analyze different rosemary leaf extracts in rats following chronic constriction injury (CCI) of sciatic nerve. Ethanol, acetone, and the innovative ultrasound-hexane extractive methods were used to obtain: EE, AE, and for hexane extracts UREprel and URE. Extracts were characterized in terms of typical constituents and repeatedly administered to CCI-rats (13-days treatment, from the day of surgery)...
October 7, 2016: Scientific Reports
Guanglin Kuang, Xu Wang, Christer Halldin, Agneta Nordberg, Bengt Långström, Hans Ågren, Yaoquan Tu
Potentiation of the function of the α7 nicotinic acetylcholine receptor (α7-nAChR) is believed to provide a possible way for the treatment of cholinergic system dysfunctions such as Alzheimer's disease and schizophrenia. Positive allosteric modulators (PAMs) are able to augment the peak current response of the endogenous agonist of α7-nAChR by binding to some allosteric sites. In this study, the binding profile of a potent type I PAM, NS-1738, with a chimera structure (termed α7-AChBP) constructed from the extracellular domain of α7-nAChR and an acetylcholine binding protein was investigated with molecular docking, molecular dynamics simulation, and free energy calculation methods...
October 12, 2016: Physical Chemistry Chemical Physics: PCCP
Omkar L Patkar, Arnauld Belmer, Josephine R Tarren, Joan Y Holgate, Selena E Bartlett
BACKGROUND: Our laboratory has previously shown that the smoking-cessation agent varenicline, an agonist/partial agonist of α4β2*, α3β4*, α3β2*, α6β2* (* indicates the possibility of additional subunits) and α7 subunits of nicotinic acetylcholine receptors (nAChRs), reduces ethanol consumption in rats only after long-term exposure (12 weeks). As compounds having partial agonistic activity on α3β4* nAChRs were shown to decrease ethanol consumption in rodents, we assessed here the involvement of the β4 subunit in the effect of varenicline in the reduction of short- and long-term binge-like ethanol drinking in mice...
October 28, 2016: Neuroscience Letters
N Rajasekar, Chandishwar Nath, Kashif Hanif, Rakesh Shukla
AIMS: Clinical studies have shown that intranasal insulin administration improves learning and memory functions. But, their neuroprotective mechanisms are largely unexplored. Therefore, we investigated the protective effect of intranasal insulin in intracerebroventricular (ICV) streptozotocin (STZ) induced memory impairment in rats. MAIN METHODS: The intranasal insulin was administered for 14days and memory function was evaluated by Morris water maze test. Cerebral blood flow (CBF) was measured by laser doppler flowmetry...
September 27, 2016: Life Sciences
Davide Barloscio, Elisa Cerri, Luciano Domenici, Renato Longhi, Clelia Dallanoce, Milena Moretti, Antonietta Vilella, Michele Zoli, Cecilia Gotti, Nicola Origlia
Although α6-contaning (α6*) nicotinic acetylcholine receptors (nAChRs) are densely expressed in the visual system, their role is not well known. We have characterized a family of toxins that are antagonists for α6β2* receptors and used one of these [RDP-MII(E11R)] to localize α6* nAChRs and investigate their impact on retinal function in adult Long-Evans rats. The α6*nAChRs in retinal tissue were localized using either a fluorescently tagged [RDP-MII(E11R)] or anti-α6-specific antibodies and found to be predominantly at the level of the ganglion cell layer...
September 28, 2016: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
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