Medical Pharmacology Commons^™

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 …

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 …

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 …

Targeting The Endocannabinoid System To Reduce Inflammatory Pain, Sudeshna Ghosh

Theses and Dissertations

The endogenous cannabinoids (endocannabinoids) anandamide (AEA) and 2-arachidonylglycerol (2-AG) exert their effects predominantly through cannabinoid CB1 and CB2 receptors, but these actions are short-lived because of rapid hydrolysis by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), respectively. Selective inhibition of either enzyme elevates CNS levels of the appropriate endocannabinoid and produces analgesic effects with fewer psychomimetic side effects than Δ9-tetrahydrocannabinol (THC), the primary active constituent of marijuana. While cannabinoid receptor agonists and FAAH inhibitors reliably produce anti-inflammatory and anti-hyperalgesic effects in the carrageenan test and other inflammatory pain models, much less is known about the consequences of inhibiting …

Artemis And Metnase Mediated Processing Of 3΄-Blocked Dna Lesions: Role In Radio/Chemoresistance And Dna Repair, Susovan Mohapatra

Theses and Dissertations

DNA double-strand breaks (DSB) with chemically modified end-termini are the most significant lesions resulting from radio/chemotherapeutic intervention of cancer and non homologous end-joining (NHEJ) factor Artemis nuclease has been implicated in the repair of such breaks. To examine whether the resolution of terminally blocked DNA DSBs is the biologically relevant function of Artemis, Artemis deficient fibroblasts were stably complemented with wild type or an endonuclease deficient D165N mutant Artemis. Physiological levels of wild type (WT) Artemis completely restored DSB repair proficiency and resistance to γ-radiation, bleomycin, and neocarzinostatin. Cells expressing the D165N mutants remained as chemo/radiosensitive and as repair deficient …

Investigating The Role Of Α6 And Α4 Containing Neuronal Nicotinic Acetylcholine Receptors In Nicotine And Cocaine Conditioned Place Preference Tests In Mice., Sarah Sanjakdar

Theses and Dissertations

Neuronal nicotinic acetylcholine receptors modulate both cholinergic and non-cholinergic synaptic transmission. Our research concerns α6 and α4 neuronal nicotinic subunits because they often co-assemble with the β2 subunit, which has abundant expression in the CNS and previous work has demonstrated that β2* nAChRs are involved in nicotine and cocaine reward. α6β2* and α4β2* nAChRs are highly expressed in midbrain, which is known to be critical for the incentive salience associated with natural and artificial (drug) reward. Our goal was to assess the role of α6β2* and α4β2* nAChRs in nicotine and cocaine reward using an unbiased conditioned place preference (CPP) …

The Role Of High Affinity Nicotinic Acetylcholine Receptors On Anxiety-Like Behavior: A Study In Female Mice, Jessicka Hall

Theses and Dissertations

Tobacco dependence is high in women who suffer from anxiety disorders yet little is known about the contributions of nicotinic acetylcholine receptors (nAChRs) on anxiety-like behavior. β2*nAChRs (*denotes assembly with other subunits) are the most abundantly expressed nAChRs in the brain yet little is known about the contributions of β2*nAChRs on anxiety-like behavior in female mice. In this study, antagonism and nicotine effects on anxiety-like behavior was investigated across the life span in 6, 12 and 24-month-old drug-naïve knockout (KO), heterozygous (HET) and a gain of function α6L9S mice and wild type (WT). HET mice showed increased sensitivity to di-hydrobeta-erythroidine …

Identifying Modulators Of The Development Of Acute Functional Tolerance To Ethanol In Caenorhabditis Elegans., Ka-Po Leung

Theses and Dissertations

Alcohol abuse is a problem in our society. There are few treatments available, in part due to the unclear molecular mechanisms of ethanol’s effects. Human studies indicate that there is a genetic component influencing disease susceptibility, and that an individual’s initial response to alcohol can predict their development of addiction. We have taken a forward genetics approach to study one component of initial response, acute functional tolerance (AFT), in Caenorhabditis elegans. We identified bet11, a mutation that causes animals to be defective in the development of AFT. Genetic analysis suggested that the gene that bet11 disrupts participates in a synthetic …

The Use Of Targeted Charge-Reversal Nanoparticles (Tcrns) To Investigate Nuclear Delivery Of Fluorescent Agents To Cancer Cells: Implications For Novel Prostate And Breast Cancer Therapy, Mario Dance

Theses and Dissertations

Nanotechnology has recently emerged as a strong contributor toward research efforts to develop targeted systems of drug delivery in cancer therapy. Our work investigates the therapeutic potential of Targeted Charge-Reversal Nanoparticles (TCRNs), a novel nanoparticle with in vitro evidence of nuclear drug delivery. Using M12 prostate cancer cells, MDA-MB-231 breast cancer cells, and modified derivatives of these cell lines, we investigated the ability of Folic Acid-tagged TCRNs to deliver Nile Red and Dimethyl Indole Redfluorescent (DiR) fluorescent dyes to the nucleus of cells using confocal microscopy and in vivo biphontonic imaging using Xenogen® Technology. Confocal imaging with the SCP28 derivative …

Role Of Autophagy In Radiosensitization Of Breast Tumor Cells, Molly L. Bristol

Theses and Dissertations

In MCF-7 breast tumor cells, ionizing radiation promoted autophagy that was cytoprotective; pharmacological or genetic interference with autophagy induced by radiation resulted in growth suppression and/or cell killing (primarily by apoptosis). The hormonally active form of vitamin D, 1,25D3, also promoted autophagy in irradiated MCF-7 cells, sensitized the cells to radiation and suppressed the proliferative recovery that occurs after radiation alone. 1,25D3 also enhanced radiosensitivity and promoted autophagy in MCF7 cells that overexpress Her-2/neu as well as in p53 mutant Hs578t breast tumor cells. In contrast, 1,25D3 failed to alter radiosensitivity or promote autophagy in the BT474 breast tumor cell …

The Effects Of Hypothermia On Status Epilepticus-Induced Acquired Epilepsy, Kristin Phillips

Theses and Dissertations

Status epilepticus (SE) is a type of neurological injury characterized by continuous seizure activity and can lead to molecular and pathophysiological alterations leading to plasticity changes. SE can lead to the development of AE by the process of epileptogenesis, which is a phenomenon that describes the transformation of normal brain tissue into a hyperexcitable neuronal population. It has been demonstrated both in vivo and in vitro that calcium (Ca2+) dynamics are severely altered during and after SE, and these changes play a major role in the progression of epileptogenesis. It has also been reported that preventing the rise in intracellular …

Intracellular Signaling Contributions To Behaviors Relevant To Nicotine Addiction, Lauren Thompson

Theses and Dissertations

Nicotine is the primary addictive substance in tobacco, and most smokers who quit will relapse within a year. Evidence shows that cigarette craving increases over time, termed “incubation.” The purpose of these studies was to see if protracted abstinence from chronic nicotine increases rat self-administration, an animal model with good face validity for human tobacco use, and if nicotine self-administration during daily exposure/after 8+ days of abstinence is regulated by extracellular signal-regulated kinase (ERK) signaling in the nucleus accumbens (NAc) shell or anterior cingulate cortex (PFC). ERK kinase inhibitor U0126 was infused in the NAc shell or PFC of Long …

Cis 3,4', 5-Trimethoxy-3'-Aminostilbene (Stilbene 5c) Induces Apoptosis And Protective Autophagy In B16f10 Melanoma Cells, Betelehem Asnake

Theses and Dissertations

The weak selectivity of chemotherapeutic drugs against tumors has sustained efforts to develop better chemotherapeutic agents that are more potent and selective at destroying tumor cell populations versus normal tissues. This project focuses on evaluating the cell killing effects of the microtubule inhibitor, stilbene 5c, against melanoma cancer. We utilized an in vitro murine melanoma model to study the effects of stilbene 5c on tumor proliferation and survival, as well as growth arrest and cell death. Our findings indicate that stilbene 5c promotes dose dependent cell death in melanomas with the induction of apoptosis and autophagy. The role of autophagy …

Targeting The Endocannabinoid System To Reduce Nociception, Lamont Booker

Theses and Dissertations

Pain of various etiologies (e.g., visceral, inflammatory) can be a debilitating disorder that presents a problem of clinical relevance. While it is known that ∆9-tetrahydrocannabinol (THC) the primary psychoactive constituent found in marijuana produces analgesia in various rodent models of pain, its pharmacological properties are overshadowed by its psychomimetic effects. THC is the primary phytocannabinoid found in marijuana though other prevalent constituents such as the phytocannabinoids (e.g., cannabidiol (CBD), cannabinol (CBN), cannabichromene (CBC), tetrahydrocannabivarin (THCV)) may possess antinociceptive actions without the psychomimetic effects associated with THC. Indeed, these phytocannabinoids act upon the endocannabinoid system (ECS) that is comprised of the …

Electrophysiological Characterization Of Enteric Neurons Isolated From The Immortomouse, Edward G. Hawkins

Theses and Dissertations

The availability of murine genetic models is extremely advantageous to studying gastrointestinal function, but the benefits afforded by studying enteric neurons in mice has been hindered by their accessibility. Fetal (E13) and 2 day post-natal (P2) enteric neuron cell lines (IM-FEN and IM-PEN, respectively) were recently developed from the H-2Kb-tsA58 immortomouse. Our goal was to identify the electrophysiological properties of these cell lines and clarify their utility as a model of enteric neurons. IM-PEN cells stained positively for the neuron specific markers βIII-tubulin and PGP9.5 and were negative for the glial cell marker S100. Detection of mRNA for TRPA1, TRPV1, …

Involvement Of P53 In The S-Phase Checkpoint During Nucleotide Deficiencies, Cortney Heyer

Theses and Dissertations

Several classes of antimetabolites have been developed for the treatment of cancer, including numerous inhibitors of nucleotide biosynthesis. N-(phosphonacetyl)-L-aspartate (PALA) and hydroxyurea (HU) are two antimetabolites that inhibit nucleotide biosynthesis; PALA inhibits de novo pyrimidine synthesis and HU inhibits the conversion of ribonucleotide diphosphates to deoxyribonucleotide diphosphates. Due to the similar mechanisms, it was thought that cancer cells would respond similarly to HU and PALA treatment. However, studies in this dissertation revealed strikingly different responses to either HU or PALA treatment in HCT116 cells. A cytoprotective S-phase arrest was activated upon HU treatment while PALA treatment failed to activate the …

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 …

Antifolate Modulators Of Amp-Activated Protein Kinase Signaling As Cancer Therapeutics, Scott Rothbart

Theses and Dissertations

Since its discovery, it was appreciated that the antifolate pemetrexed had multiple targets within folate metabolism. This laboratory was instrumental in showing that pemetrexed elicited its primary action as a thymidylate synthase inhibitor. Unusual for an antifolate, pemetrexed showed significant clinical activity against malignant pleural mesothelioma and non-small cell lung cancer. Accordingly, the FDA recently issued first-line approvals for pemetrexed in these diseases, leading us to question whether the effects of pemetrexed on other folate-dependent targets could explain this atypical clinical activity of the drug. Studies in this dissertation showed that in addition to thymidylate synthase inhibition, pemetrexed was also …

Cannabinoid Receptors In The 3d Reconstructed Mouse Brain: Function And Regulation, Peter Nguyen

Theses and Dissertations

CB1 receptors (CB1R) mediate the psychoactive and therapeutic effects of cannabinoids including ∆9-tetrahydrocannabinol (THC), the main psychoactive constituent in marijuana. However, therapeutic use is limited by side effects and tolerance and dependence with chronic administration. Tolerance to cannabinoid-mediated effects is associated with CB1R adaptations, including desensitization (receptor-G-protein uncoupling) and downregulation (receptor degradation). The objectives of this thesis are to investigate the regional-specificity in CB1R function and regulation. Previous studies have investigated CB1Rs in a subset of regions involved in cannabinoid effects, but an inclusive regional comparison of the relative efficacies of different classes of cannabinoids to activate G-proteins has not …

The Impact Of Adolescent Nicotine Exposure On Drug Dependence In Adulthood, Mai Alajaji

Theses and Dissertations

Nicotine is one of the first and most commonly abused drugs in adolescence. According to The Center for Disease Control, every day more than 6000 adolescents try their first cigarette and over 3000 of them become daily smokers. Smoking among adolescents is a strong predictor of future drug abuse and dependence in adulthood. A number of studies has suggests that adolescents pre-exposed to nicotine may suffer permanent disruption of the brain’s reward systems through changes in dopamine receptor function. We hypothesize that nicotine exposure during adolescence causes long lasting neurobiological alterations that increase the likelihood of cocaine use in adulthood. …

Cell Death And Sustained Senescence Arrest In Colon Carcinoma And Melanoma Tumor Cells In Response To The Novel Microtubule Poison, Jg-03-14, Jonathan Biggers

Theses and Dissertations

Previous studies from this and other laboratories have shown that the novel microtubule poison, JG-03-14, which binds to the colchicine binding site of tubulin, has the capacity to promote both autophagy and apoptosis in breast tumor cells, as well as interfering with endothelial cell function and potentially disrupting tumor vasculature. The current work was designed to investigate the interaction between JG-03-14 and cell culture models of colon carcinoma and melanoma, specifically HCT116 human colon carcinoma cells and B16F10 murine melanoma cells. In both cases, JG-03-14 promoted death in the bulk of the treated population. FACS analysis, DAPI and TUNEL staining …

The Mechanism Of Mitochondrial Folate Transport By The Mitochondrial Folate Transporter, Scott Alan Lawrence

Theses and Dissertations

The mitochondrial folate transport protein (MFT) functions to transport folates into the mitochondrial matrix. The MFT is a member of a mitochondrial carrier family (MCF) of proteins that have a high degree of sequence and structural similarities, yet they transport vastly different substrates at high specificities. In this dissertation research, the folate-specific transport mechanism of the MFT was explored using experimental and computational techniques. MFT residues that differed from MCF consensus residues in conserved PxD/ExxK/R motifs and at a predicted substrate-binding site common to all MCF proteins were investigated. Site-directed mutagenesis of these anomalous residues in the MFT revealed that …

Differential Roles Of The Two Major Endocannabinoid Hydrolyzing Enzymes In Cannabinoid Receptor Tolerance And Somatic Withdrawal, Joel Schlosburg

Theses and Dissertations

While there is currently active debate over possible therapeutic applications of marijuana and cannabis-based compounds, consistently their primary drawbacks have been the psychoactive properties, dependence, and abuse potential. Prolonged administration of ∆9-tetrahydrocannabinol (THC), the primary psychoactive constituent in marijuana, demonstrates both tolerance and physical withdrawal in both preclinical and clinical studies. Repeated THC administration also produces CB1 receptor adaptations in the form of reduced activation of receptors, along with a downregulation of membrane surface receptors, in many brain regions involved in THC-associated behaviors. The increased need for drug to maintain therapeutic effects, and a withdrawal syndrome following discontinuation of use, …

Modulation Of Cocaine-Like Behavioural Activity By Serotonin Uptake Inhibition Relative To The Effects Of The Novel And Selective Dopamine Transporter Inhibitor, D-84, Angela Batman

Theses and Dissertations

Cocaine dependence is a major health concern worldwide, but despite this high rate of abuse there are currently no approved therapies for cocaine dependence. Replacement pharmacotherapies are one possible approach for treating cocaine dependence, and identification of such therapeutics for cocaine abuse is the long-term goal of this research. Cocaine binds to, and inhibits uptake at the dopamine (DAT), serotonergic (SERT) and noradrenaline (NET) uptake transporters, but studies have shown that cocaine produces its strong behavioural and positive reinforcing effects through inhibition of the DAT. To this end a great number of diverse, non-selective DAT-inhibiting compounds have been investigated as …

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 …

Effects Of Cannabinoid Receptor Interacting Protein (Crip1a) On Cannabinoid Receptor (Cb1) Function, Tricia Smith

Theses and Dissertations

EFFECTS OF CANNABINOID RECEPTOR INTERACTING PROTEIN (CRIP1a) ON CANNABINOID (CB1) RECEPTOR FUNCTION. By Tricia Hardt Smith, B.S., M.S. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University Virginia Commonwealth University, 2009. Major Director: Dana E. Selley, Ph.D., Department of Pharmacology and Toxicology This dissertation examines modulation of cannabinoid CB1 receptor function by Cannabinoid Receptor Interacting Protein (CRIP1a), a novel protein that binds the C-terminus of CB1 receptors. In Human embryonic kidney cells expressing human CB1 receptors (hCB1-HEK) and hCB1-HEK cells stably co-expressing CRIP1a (hCB1-HEK-CRIP1a), quantitative immunoblotting revealed a CRIP1a/CB1 …

Denitration In Colonic Smooth Muscle, Seemab Malick

Theses and Dissertations

Tyrosine nitration results in altered function of smooth muscle voltage-gated L-type calcium channel. We explored the possibility that smooth muscle contains denitrase activity to allow functional recovery of the calcium channel without requiring synthesis of new channel proteins. Following peroxynitrite treatment of mouse colonic smooth muscle strips, CaCl2 (1 mM)-induced smooth muscle contraction was significantly reduced by 67% (P ≤ 0.05), which reversed by approximately 86% upon periodic washing within 2 hr period (P ≤ 0.001). The effect of the c-Src kinase inhibitor, PP2, on muscle contraction was also restored after 2 hr post-peroxynitrite treatment consistent with the thesis that …

Inhibition Of The Calcium Plateau Following In Vitro Status Epilepticus Prevents The Development Of Spontaneous Recurrent Epileptiform Discharges, Nisha Nagarkatti

Theses and Dissertations

Status epilepticus (SE) is a major clinical emergency resulting in continuous seizure activity that can cause brain injury and many molecular and pathophysiologic changes leading to neuronal plasticity. The neuronal plasticity following SE-induced brain injury can initiate epileptogenesis and lead to the ultimate expression of acquired epilepsy (AE), characterized clinically by spontaneous, recurrent seizures. Epileptogenesis is the process wherein healthy brain tissue is transformed into hyperexcitable neuronal networks that produce AE. Understanding these alterations induced by brain injury is an important clinical challenge and can lend insight into possible new therapeutic targets to halt the development of AE. Currently there …

Behavioral And Molecular Analysis Of Individual Variation In Ethanol Drinking, Jennifer Wolstenholme

Theses and Dissertations

A majority of Americans regularly consume alcohol, but the risk factors leading to excessive drinking and alcohol abuse are unevenly distributed throughout the population. Genetic differences can account for only 40-60% of this variability. While variations in ethanol preference drinking in rodent models have been reported, the neurobiological factors underlying these behaviors are still not completely understood. Thus, these studies were designed to determine behavioral and molecular factors associated with the initiation of ethanol drinking preference in an inbred mouse model. We harnessed the power of inter-individual variation of ethanol drinking within an inbred mouse strain to essentially eliminate genetic …