Medicine and Health Sciences Commons^™

Sorafenib, Rapamycin, And Venetoclax Attenuate Doxorubicin-Induced Senescence And Promote Apoptosis In Hct116 Cells, Homood M. As Sobeai, Munirah Alohaydib, Ali R. Alhoshani, Khalid Alhazzani, Mashal M. Almutairi, Tareq Saleh, David A. Gewirtz, Moureq R. Alotiabi

Pharmacology and Toxicology Publications

Emerging evidence has shown that the therapy-induced senescent growth arrest in cancer cells is of durable nature whereby a subset of cells can reinstate proliferative capacity. Promising new drugs named senolytics selectively target senescent cells and commit them into apoptosis. Accordingly, senolytics have been proposed as adjuvant cancer treatment to cull senescent tumor cells, and thus, screening for agents that exhibit senolytic properties is highly warranted. Our study aimed to investigate three agents, sorafenib, rapamycin, and venetoclax for their senolytic potential in doxorubicin-induced senescence in HCT116 cells. HCT116 cells were treated with one of the three agents, sorafenib …

Multiple Blood-Brain Barrier Transport Mechanisms Limit Bumetanide Accumulation, And Therapeutic Potential, In The Mammalian Brain, Kerstin Römermann, Maren Fedrowitz, Philip Hampel, Edith Kaczmarek, Kathrin Töllner, Thomas Erker, Douglas H. Sweet, Wolfgang Löscher

Pharmacology and Toxicology Publications

There is accumulating evidence that bumetanide, which has been used over decades as a potent loop diuretic, also exerts effects on brain disorders, including autism, neonatal seizures, and epilepsy, which are not related to its effects on the kidney but rather mediated by inhibition of the neuronal Na-K-C1 cotransporter isoform NKCC1. However, following systemic administration, brain levels of bumetanide are typically below those needed to inhibit NKCC1, which critically limits its clinical use for treating brain disorders. Recently, active efflux transport at the blood-brain barrier (BBB) has been suggested as a process involved in the low brain:plasma ratio of bumetanide, …

Development Of A Translational Model To Screen Medications For Cocaine Use Disorder I: Choice Between Cocaine And Food In Rhesus Monkeys, Amy R. Johnson

Pharmacology and Toxicology Publications

Background

Homologous cocaine self-administration procedures in laboratory animals and humans may facilitate translational research for medications development to treat cocaine dependence. This study, therefore, sought to establish choice between cocaine and an alternative reinforcer in rhesus monkeys responding under a procedure back-translated from previous human studies and homologous to a human laboratory procedure described in a companion paper.

Methods

Four rhesus monkeys with chronic indwelling intravenous catheters had access to cocaine injections (0, 0.043, 0.14, or 0.43 mg/kg/injection) and food (0, 1, 3, or 10 1 g banana-flavored food pellets). During daily 5 h sessions, a single cocaine dose and …

Effects Of 7-Day Repeated Treatment With The 5-Ht2a Inverse Agonist/Antagonist Pimavanserin On Methamphetamine Vs. Food Choice In Male Rhesus Monkeys, Matthew L. Banks L. Banks

Pharmacology and Toxicology Publications

Background

Preclinical drug vs. food choice is an emerging group of drug self-administration procedures that have shown predictive validity to clinical drug addiction. Emerging data suggest that serotonin (5-HT)_2A receptors modulate mesolimbic dopamine function, such that 5-HT_2A antagonists blunt the abuse-related neurochemical effects of monoamine transporter substrates, such as amphetamine or methamphetamine. Whether subchronic 5-HT_2A antagonist treatment attenuates methamphetamine reinforcement in any preclinical drug self-administration procedure is unknown. The study aim was therefore to determine 7-day treatment effects with the 5-HT_2A inverse agonist/antagonist pimavanserin on methamphetamine vs. food choice in monkeys.

Methods …

Identification Of The Metabolic Enzyme Involved Morusin Metabolism And Characterization Of Its Metabolites By Ultraperformance Liquid Chromatogaphy Quadrupole Time-Of-Flight Mass Spectrometry (Uplc/Q-Tof-Ms/Ms), Xianbao Shi, Brianna Mackie, Gang Zhang, Shuman Yang, Yonggui Song, Dan Su, Yali Liu, Lina Shan

Pharmacology and Toxicology Publications

Morusin, the important active component of a traditional Chinese medicine, Morus alba L., has been shown to exhibit many vital pharmacological activities. In this study, six recombinant CYP450 supersomes and liver microsomes were used to perform metabolic studies. Chemical inhibition studies and screening assays with recombinant human cytochrome P450s were also used to characterize the CYP450 isoforms involved in morusin metabolism. The morusin metabolites identified varied greatly among different species. Eight metabolites of morusin were detected in the liver microsomes from pigs (PLMs), rats (RLMs), and monkeys (MLMs) by LC-MS/MS and six metabolites were detected in the liver microsomes from …

Time-Course Analysis Of Brain Regional Expression Network Responses To Chronic Intermittent Ethanol And Withdrawal: Implications For Mechanisms Underlying Excessive Ethanol Consumption, Maren L. Smith, Marcelo F. Lopez, Kellie Archer, Aaron R. Wolen, Howard C. Becker, Michael F. Miles

Pharmacology and Toxicology Publications

Long lasting abusive consumption, dependence, and withdrawal are characteristic features of alcohol use disorders (AUD). Mechanistically, persistent changes in gene expression are hypothesized to contribute to brain adaptations leading to ethanol toxicity and AUD. We employed repeated chronic intermittent ethanol (CIE) exposure by vapor chamber as a mouse model to simulate the cycles of ethanol exposure and withdrawal commonly seen with AUD. This model has been shown to induce progressive ethanol consumption in rodents. Brain CIE-responsive expression networks were identified by microarray analysis across five regions of the mesolimbic dopamine system and extended amygdala with tissue harvested from 0-hours to …

Redox Regulation Of Nlrp3 Inflammasomes: Ros As Trigger Or Effector?, Justine M. Abais, Min Xia, Yang Zhang, Krishna M. Boini, Pin-Lan Li

Pharmacology and Toxicology Publications

Significance: Inflammasomes are multiprotein complexes localized within the cytoplasm of the cell that are responsible for the maturation of proinflammatory cytokines such as interleukin-1β (IL-1β) and IL-18, and the activation of a highly inflammatory form of cell death, pyroptosis. In response to infection or cellular stress, inflammasomes are assembled, activated, and involved in host defense and pathophysiology of diseases. Clarification of the molecular mechanisms leading to the activation of this intracellular inflammatory machinery may provide new insights into the concept of inflammation as the root of and route to human diseases. Recent Advances: The activation of inflammasomes, specifically the most …

Adipose-Derived Mesenchymal Stem Cells Improve Glucose Homeostasis In High-Fat Diet-Induced Obese Mice, Mingjun Cao, Qingjie Pan, Huanshen Dong, Xinxu Yuan, Yang Li, Zhen Sun, Xiao Dong, Hongjun Wang

Pharmacology and Toxicology Publications

Introduction

Effective therapies for obesity and diabetes are still lacking. The aim of this study was to evaluate whether a single intravenous infusion of syngeneic adipose-derived mesenchymal stem cells (ASCs) can reduce obesity, lower insulin resistance, and improve glucose homeostasis in a high-fat diet-induced obese (DIO) mouse model.

Methods

Seven-week-old C57BL/6 mice were fed a high-fat diet for 20 weeks to generate the DIO mouse model. Mice were given a single intravenous infusion of ex vivo expanded syngeneic ASCs at 2 × 10 ⁶ cells per mouse. DIO or CHOW mice injected with saline were used as controls. Body weights, …

Metabolic Interplay Between Astrocytes And Neurons Regulates Endocannabinoid Action, Andreu Viader, Jacqueline L. Blankman, Peng Zhong, Xiaojie Liu, Joel E. Scholsburg, Christopher M. Joslyn, Qing-Song Liu, Aaron J. Tomarchio, Aron H. Lichtman, Dana E. Selley, Laura J. Sim-Selley, Benjamin F. Cravatt

Pharmacology and Toxicology Publications

The endocannabinoid 2-arachidonoylglycerol (2-AG) is a retrograde lipid messenger that modulates synaptic function, neurophysiology, and behavior. 2-AG signaling is terminated by enzymatic hydrolysis—a reaction that is principally performed by monoacylglycerol lipase (MAGL). MAGL is broadly expressed throughout the nervous system, and the contributions of different brain cell types to the regulation of 2-AG activityin vivo remain poorly understood. Here, we genetically dissect the cellular anatomy of MAGL-mediated 2-AG metabolism in the brain and show that neurons and astrocytescoordinately regulate 2-AG content and endocannabinoid-dependent forms of synaptic plasticity and behavior. We also find that astrocytic MAGL is mainly responsible …

Stem Cell Conditioned Culture Media Attenuated Albumin-Induced Epithelial– Mesenchymal Transition In Renal Tubular Cells, Junping Hu, Qing Zhu, Pin-Lan Li, Weili Wang, Fan Yi, Ningjun Li

Pharmacology and Toxicology Publications

Background: Proteinuria-induced epithelial-mesenchymal transition (EMT) plays an important role in progressive renal tubulointerstitial fibrosis in chronic renal disease. Stem cell therapy has been used for different diseases. Stem cell conditioned culture media (SCM) exhibits similar beneficial effects as stem cell therapy. The present study tested the hypothesis that SCM inhibits albumin-induced EMT in cultured renal tubular cells. Methods: Rat renal tubular cells were treated with/without albumin (20 µmg/ml) plus SCM or control cell media (CCM). EMT markers and inflammatory factors were measured by Western blot and fluorescent images. Results: Albumin induced EMT as shown by significant decreases in levels of …

Differing Roles Of Autophagy In Hiv-Associated Neurocognitive Impairment And Encephalitis With Implications For Morphine Co-Exposure, Seth M. Dever, Myosotys Rodriguez, Jessica Lapierre, Blair N. Costin, Nazira El-Hage

Pharmacology and Toxicology Publications

We investigated the role of autophagy in HIV-infected subjects with neurocognitive impairment (NCI) ± HIV encephalitis (HIVE), many of which had a history of polysubstance abuse/dependence, using post-mortem brain tissues to determine whether differences in autophagy related factors may be more associated with NCI or NCI-encephalitis. Using qRT-PCR, we detected significant differences in gene expression levels with SQSTM1, LAMP1 higher in HIV-infected subjects without NCI while ATG5, SQSTM1 were then lower in HIV infection/NCI and ATG7, SQSTM1 being higher in NCI-HIVE. Immunohistochemical labeling of these autophagy associated proteins (also including Beclin 1 and LC3B) in Iba1-positive microglial cells showed generally …

Contribution Of Nrf2 To Atherogenic Phenotype Switching Of Coronary Arterial Smooth Muscle Cells Lacking Cd38 Gene, Ming Xu, Xiao-Xue Li, Lei Wang, Mi Wang, Yang Zhang, Pin-Lan Li

Pharmacology and Toxicology Publications

Background/Aims: Recent studies have indicated that CD38 gene deficiency results in dedifferentiation or transdifferentiation of arterial smooth muscle cells upon atherogenic stimulations. However, the molecular mechanisms mediating this vascular smooth muscle (SMC) phenotypic switching remain unknown. Methods & Results: In the present study, we first characterized the phenotypic change in the primary cultures of coronary arterial myocytes (CAMs) from CD38-/- mice. It was shown that CD38 deficiency decreased the expression of contractile marker calponin, SM22α and α-SMA but increased the expression of SMC dedifferentiation marker, vimentin, which was accompanied by enhanced cell proliferation. This phenotypic change in CD38-/- CAMs was …

Concentration-Dependent Diversification Effects Of Free Cholesterol Loading On Macrophage Viability And Polarization, Xiaoyang Xu, Aolin Zhang, Ningjun Li, Pin-Lan Li, Fan Zhang

Pharmacology and Toxicology Publications

Background/Aims: The accumulation of free cholesterol in atherosclerotic lesions has been well documented in both animals and humans. In studying the relevance of free cholesterol buildup in atherosclerosis, contradictory results have been generated, indicating that free cholesterol produces both pro- and anti-atherosclerosis effects in macrophages. This inconsistency might stem from the examination of only select concentrations of free cholesterol. In the present study, we sought to investigate the implication of excess free cholesterol loading in the pathophysiology of atherosclerosis across a broad concentration range from (in µg/ml) 0 to 60. Methods:Macrophage viability was determined by measuring formazan formation and …

Effects Of Menthol On Nicotine Pharmacokinetic, Pharmacology And Dependence In Mice, Sharki D. Alsharari, Justin R. King, Jacob C. Nordman, Pretal P. Muldoon, Asti Jackson, Andy Z. X. Zhu, Rachel F. Tyndale, Nadine Kabbani, M. Imad Damaj

Pharmacology and Toxicology Publications

Although menthol, a common flavoring additive to cigarettes, has been found to impact the addictive properties of nicotine cigarettes in smokers little is known about its pharmacological and molecular actions in the brain. Studies were undertaken to examine whether the systemic administration of menthol would modulate nicotine pharmacokinetics, acute pharmacological effects (antinociception and hypothermia) and withdrawal in male ICR mice. In addition, we examined changes in the brain levels of nicotinic receptors of rodents exposed to nicotine and menthol. Administration of i.p. menthol significantly decreased nicotine’s clearance (2-fold decrease) and increased its AUC compared to i.p. vehicle treatment. In addition, …

The Omega-3 Fatty Acid Eicosapentaenoic Acid Is Required For Normal Alcohol Response Behaviors In C. Elegans, Richard C. Raabe, Laura D. Mathies, Andrew G. Davies, Jill C. Bettinger

Pharmacology and Toxicology Publications

Alcohol addiction is a widespread societal problem, for which there are few treatments. There are significant genetic and environmental influences on abuse liability, and understanding these factors will be important for the identification of susceptible individuals and the development of effective pharmacotherapies. In humans, the level of response to alcohol is strongly predictive of subsequent alcohol abuse. Level of response is a combination of counteracting responses to alcohol, the level of sensitivity to the drug and the degree to which tolerance develops during the drug exposure, called acute functional tolerance. We use the simple and well-characterized nervous system of Caenorhabditis …

Specific Localization Of Β-Arrestin2 In Myenteric Plexus Of Mouse Gastrointestinal Tract, Hercules T. Maguma, Dipanjana D. De, Sukhada Bhave, William L. Dewey, Hamid I. Akbarali

Pharmacology and Toxicology Publications

Abstract

β-arrestin2 is a key molecule involved in signaling and internalization of activated G protein-coupled receptors including µ-opioid receptors (MOR). Previously we have shown that decreased expression of β-arrestin2 upon chronic morphine is associated with the development of opioid tolerance in the gastrointestinal tract. However, the localization of β-arrestin2 within the gastrointestinal wall is not known. In this study we found that β-arrestin2 is localized in the soma of a select group of neurons in the myenteric ganglia but not in smooth muscle. The density of β-arestin2 was significantly higher in the ileum than the colon. We identified four variants …

Activation Of Nlrp3 Inflammasomes Enhances Macrophage Lipid-Deposition And Migration: Implication Of A Novel Role Of Inflammasome In Atherogenesis, Xiang Li, Yang Zhang, Min Xia, Erich Gulbins, Krishna M. Boini, Pin-Lan Li

Pharmacology and Toxicology Publications

Although Nlrp3 inflammasome activation in macrophages has been shown to be critical for the development of atherosclerosis upon atherogenic stimuli, it remains unknown whether activated Nlrp3 inflammasomes by other non-atherogenic stimuli induce alterations in macrophages that may contribute in the concert with other factors to atherogenesis. Thus, the present study tested the hypothesis that activation of Nlrp3 inflammasomes by ATP, which is a classical non-lipid danger stimulus, enhances the migration of macrophage and increases lipids deposition in macrophages accelerating foam cell formation. We first demonstrated that extracellular ATP (2.5 mM) markedly increased the formation and activation of Nlrp3 inflammasomes in …

Ethanol Regulation Of Serum Glucocorticoid Kinase 1 Expression In Dba2/J Mouse Prefrontal Cortex, Blair N. Costin, Seth M. Dever, Michael F. Miles

Pharmacology and Toxicology Publications

Background

We previously identified a group of glucocorticoid-responsive genes, including Serum Glucocorticoid kinase 1 (Sgk1), regulated by acute ethanol in prefrontal cortex of DBA2/J mice. Acute ethanol activates the hypothalamic pituitary adrenal axis (HPA) causing release of glucocorticoids. Chronic ethanol dysregulates the HPA response in both humans and rodents, possibly contributing to important interactions between stress and alcoholism. Because Sgk1regulates ion channels and learning and memory, we hypothesized that Sgk1 contributes to HPA-dependent acute and adaptive neuronal responses to ethanol. These studies characterized acute and chronic ethanol regulation of Sgk1 mRNA and protein and their relationship with ethanol actions …

Fyn-Dependent Gene Networks In Acute Ethanol Sensitivity, Sean P. Farris, Michael F. Miles

Pharmacology and Toxicology Publications

Studies in humans and animal models document that acute behavioral responses to ethanol are predisposing factor for the risk of long-term drinking behavior. Prior microarray data from our laboratory document strain- and brain region-specific variation in gene expression profile responses to acute ethanol that may be underlying regulators of ethanol behavioral phenotypes. The non-receptor tyrosine kinase Fyn has previously been mechanistically implicated in the sedative-hypnotic response to acute ethanol. To further understand how Fyn may modulate ethanol behaviors, we used whole-genome expression profiling. We characterized basal and acute ethanol-evoked (3 g/kg) gene expression patterns in nucleus accumbens (NAC), prefrontal cortex …

Contribution Of Nadph Oxidase To Membrane Cd38 Internalization And Activation In Coronary Arterial Myocytes, Ming Xu, Xiao-Xue Li, Joseph K. Ritter, Justine M. Abais, Yang Zhang, Pin-Lan Li

Pharmacology and Toxicology Publications

The CD38-ADP-ribosylcyclase-mediated Ca2+ signaling pathway importantly contributes to the vasomotor response in different arteries. Although there is evidence indicating that the activation of CD38-ADP-ribosylcyclase is associated with CD38 internalization, the molecular mechanism mediating CD38 internalization and consequent activation in response to a variety of physiological and pathological stimuli remains poorly understood. Recent studies have shown that CD38 may sense redox signals and is thereby activated to produce cellular response and that the NADPH oxidase isoform, NOX1, is a major resource to produce superoxide (O2·−) in coronary arterial myocytes (CAMs) in response to muscarinic receptor agonist, which uses CD38-ADP-ribosylcyclase …

Cannabinoid Cb2 Receptors Regulate Central Sensitization And Pain Responses Associated With Osteoarthritis Of The Knee Joint, James J. Burston, David R. Sagar, Pin Shao, Mingfeng Bai, Emma King, Louis Brailsford, Jenna M. Turner, Gareth J. Hathway, Andrew J. Bennett, David A. Walsh, David A. Kendall, Aron H. Lichtman, Victoria Chapman

Pharmacology and Toxicology Publications

Osteoarthritis (OA) of the joint is a prevalent disease accompanied by chronic, debilitating pain. Recent clinical evidence has demonstrated that central sensitization contributes to OA pain. An improved understanding of how OA joint pathology impacts upon the central processing of pain is crucial for the identification of novel analgesic targets/new therapeutic strategies.

Inhibitory cannabinoid 2 (CB2) receptors attenuate peripheral immune cell function and modulate central neuro-immune responses in models of neurodegeneration. Systemic administration of the CB2 receptor agonist JWH133 attenuated OA-induced pain behaviour, and the changes in circulating pro- and anti-inflammatory cytokines exhibited in this model. Electrophysiological studies revealed that …

Low Dose Nicotine And Antagonism Of Β2 Subunit Containing Nicotinic Acetylcholine Receptors Have Similar Effects On Affective Behavior In Mice, Shawn M. Anderson, Darlene H. Brunzell

Pharmacology and Toxicology Publications

Nicotine leads to both activation and desensitization (inactivation) of nicotinic acetylcholine receptors (nAChRs). This study tested the hypothesis that nicotine and a selective antagonist of β2*nAChRs would have similar effects on affective behavior. Adult C57BL/6J male mice were tested in a conditioned emotional response (CER) assay which evaluates the ability of an aversive stimulus to inhibit goal-directed behavior. Mice lever-pressed for a saccharin reinforcer according to a variable schedule of reinforcement during sessions in which two presentations of a compound light/tone conditioned stimulus (CS) co-terminated with a 0.1 or 0.3 mA, 0.5 s footshock unconditioned stimulus (US). During testing in …

Mice Deficient In Gem Gtpase Show Abnormal Glucose Homeostasis Due To Defects In Beta-Cell Calcium Handling, Jenny E. Gunton, Mary Sisavanh, Rebecca A. Stokes, Jon Satin, Leslie S. Satin, Min Zhang, Sue M. Liu, Weikang Cai, Kim Cheng, Gregory J. Cooney, D. Ross Laybutt, Trina So, Juan-Carlos Molero, Shane T. Grey, Douglas A. Andres, Michael S. Rolph, Charles R. Mackay

Pharmacology and Toxicology Publications

Aims and Hypothesis

Glucose-stimulated insulin secretion from beta-cells is a tightly regulated process that requires calcium flux to trigger exocytosis of insulin-containing vesicles. Regulation of calcium handling in beta-cells remains incompletely understood. Gem, a member of the RGK (Rad/Gem/Kir) family regulates calcium channel handling in other cell types, and Gem over-expression inhibits insulin release in insulin-secreting Min6 cells. The aim of this study was to explore the role of Gem in insulin secretion. We hypothesised that Gem may regulate insulin secretion and thus affect glucose tolerance in vivo.

Methods

Gem-deficient mice were generated and their metabolic phenotype characterised by …

Acid Sphingomyelinase Gene Knockout Ameliorates Hyperhomocysteinemic Glomerular Injury In Mice Lacking Cystathionine-Β-Synthase, Krishna M. Boini, Min Xia, Justine M. Abais, Ming Xu, Cai-Xia Li, Pin-Lan Li

Pharmacology and Toxicology Publications

Acid sphingomyelinase (ASM) has been implicated in the development of hyperhomocysteinemia (hHcys)-induced glomerular oxidative stress and injury. However, it remains unknown whether genetically engineering of ASM gene produces beneficial or detrimental action on hHcys-induced glomerular injury. The present study generated and characterized the mice lacking cystathionine β-synthase (Cbs) and Asm mouse gene by cross breeding Cbs+/− and Asm+/− mice. Given that the homozygotes of Cbs−/−/Asm−/− mice could not survive for 3 weeks. Cbs+/−/Asm+/+, Cbs+/−/Asm+/− and Cbs+/−/Asm−/− as well as their Cbs wild type littermates were used to study the role of Asm−/− under a background of Cbs+/− with hHcys. HPLC …

Discovery Of Prostamide F2Α And Its Role In Inflammatory Pain And Dorsal Horn Nociceptive Neuron Hyperexcitability, Luisa Gatta, Fabiana Piscitelli, Catia Giordano, Serana Boccella, Aron H. Lichtman, Sebatino Maione, Vincenzo Di Marzo

Pharmacology and Toxicology Publications

It was suggested that endocannabinoids are metabolized by cyclooxygenase (COX)-2 in the spinal cord of rats with kaolin/λ-carrageenan-induced knee inflammation, and that this mechanism contributes to the analgesic effects of COX-2 inhibitors in this experimental model. We report the development of a specific method for the identification of endocannabinoid COX-2 metabolites, its application to measure the levels of these compounds in tissues, and the finding of prostamide F2α (PMF2α) in mice with knee inflammation. Whereas the levels of spinal endocannabinoids were not significantly altered by kaolin/λ-carrageenan-induced knee inflammation, those of the COX-2 metabolite of AEA, PMF2α, were strongly elevated. The …

Lipid Environment Modulates The Development Of Acute Tolerance To Ethanol In Caenorhabditis Elegans, Jill C. Bettinger, Kapo Leung, Mia H. Bolling, Andrew D. Goldsmith, Andrew G. Davies

Pharmacology and Toxicology Publications

The development of tolerance to a drug at the level of the neuron reflects a homeostatic mechanism by which neurons respond to perturbations of their function by external stimuli. Acute functional tolerance (AFT) to ethanol is a fast compensatory response that develops within a single drug session and normalizes neuronal function despite the continued presence of the drug. We performed a genetic screen to identify genes required for the development of acute functional tolerance to ethanol in the nematode C. elegans. We identified mutations affecting multiple genes in a genetic pathway known to regulate levels of triacylglycerols (TAGs) via …

Morphine Decreases Enteric Neuron Excitability Via Inhibition Of Sodium Channels, Tricia H. Smith, John R. Grider, William L. Dewey, Hamid I. Akbarali

Pharmacology and Toxicology Publications

Gastrointestinal peristalsis is significantly dependent on the enteric nervous system. Constipation due to reduced peristalsis is a major side-effect of morphine, which limits the chronic usefulness of this excellent pain reliever in man. The ionic basis for the inhibition of enteric neuron excitability by morphine is not well characterized as previous studies have mainly utilized microelectrode recordings from whole mount myenteric plexus preparations in guinea pigs. Here we have developed a Swiss-Webster mouse myenteric neuron culture and examined their electrophysiological properties by patch-clamp techniques and determined the mechanism for morphine-induced decrease in neuronal excitability. Isolated neurons in culture were confirmed …

Genomic Analysis Of Individual Differences In Ethanol Drinking: Evidence For Non-Genetic Factors In C57bl/6 Mice, Jennifer T. Wolstenholme, Jon A. Warner, Maria I. Capparuccini, Kellie J. Archer, Keith L. Shelton, Michael F. Miles

Pharmacology and Toxicology Publications

Genetic analysis of factors affecting risk to develop excessive ethanol drinking has been extensively studied in humans and animal models for over 20 years. However, little progress has been made in determining molecular mechanisms underlying environmental or non-genetic events contributing to variation in ethanol drinking. Here, we identify persistent and substantial variation in ethanol drinking behavior within an inbred mouse strain and utilize this model to identify gene networks influencing such “non-genetic” variation in ethanol intake. C57BL/6NCrl mice showed persistent inter-individual variation of ethanol intake in a two-bottle choice paradigm over a three-week period, ranging from less than 1 g/kg …

Metabolic Oscillations In Pancreatic Islets Depend On The Intracellular Ca2+ Level But Not Ca2+ Oscillations, Matthew J. Merrins, Bernard Fendler, Min Zhang, Arthur Sherman, Richard Bertram, Leslie S. Satin

Pharmacology and Toxicology Publications

Abstract

Plasma insulin is pulsatile and reflects oscillatory insulin secretion from pancreatic islets. Although both islet Ca²⁺ and metabolism oscillate, there is disagreement over their interrelationship, and whether they can be dissociated. In some models of islet oscillations, Ca²⁺ must oscillate for metabolic oscillations to occur, whereas in others metabolic oscillations can occur without Ca²⁺ oscillations. We used NAD(P)H fluorescence to assay oscillatory metabolism in mouse islets stimulated by 11.1 mM glucose. After abolishing Ca²⁺ oscillations with 200 μM diazoxide, we observed that oscillations in NAD(P)H persisted in 34% of islets (n = 101). …

A Transposon In Comt Generates Mrna Variants And Causes Widespread Expression And Behavioral Differences Among Mice, Zhengsheng Li, Megan K. Mulligan, Xusheng Wang, Michael F. Miles, Lu Lu, Robert W. Williams

Pharmacology and Toxicology Publications

Background

Catechol-O-methyltransferase (COMT) is a key enzyme responsible for the degradation of dopamine and norepinephrine. COMT activity influences cognitive and emotional states in humans and aggression and drug responses in mice. This study identifies the key sequence variant that leads to differences in Comt mRNA and protein levels among mice, and that modulates synaptic function and pharmacological and behavioral traits.

Methodology/Principal Findings

We examined Comt expression in multiple tissues in over 100 diverse strains and several genetic crosses. Differences in expression map back to Comt and are generated by a 230 nt insertion of a B2 short interspersed element (B2 …