Pharmacology Commons^™

Ovine Maternal And Fetal Cardiovascular Effects Of The Serotonergic Agonist R(-)-2,5-Dimethoxy-4-Methyl-Amphetamine And Characterization Of Serotonergic Receptors In The Ovine Uterine And Umbilical Vessels , Lubo Zhang

Lubo Zhang, PhD

Maternal administration of 2,5-dimethoxy-4-methyl-amphetamine (DOM) produced a dose-dependent increase in maternal and fetal arterial blood pressure and a fall in the heart rate. Maternal uterine artery blood flow was dramatically decreased following DOM administration, and the uterine vascular resistance increased. These responses were accompanied by fetal hypoxemia, combined metabolic and respiratory acidosis, hypertension and bradycardia. The changes in the blood flow and the vascular resistance produced by DOM were always smaller in fetal umbilical arteries than in the maternal uterine artery. Maternal administration of ketanserin (1 mg/kg) 30 minutes prior to the administration of DOM inhibited maternal and fetal cardiovascular …

Effects Of Anandamide Administration On Components Of Reward Processing, Howard C. Cromwell

Howard Casey Cromwell

Pharmacological And Antihyperalgesic Properties Of The Novel Α2/3 Preferring Gabaa Receptor Ligand Mp-Iii-024., Bradford D. Fischer, Raymond J. Schlitt, Bryan Z. Hamade, Sabah Rehman, Margot Ernst, Michael M. Poe, Guanguan Li, Revathi Kodali, Leggy A. Arnold, James M. Cook

Bradford Fischer

In Vitro Studies On Metabolism Of Salvinorin A, Lukasz M. Kutrzeba, Vardan T. Karamyan, Robert C. Speth, John S. Williamson, Jordan K. Zjawiony

John S. Williamson

Microbial transformation of natural products is a well established model for mammalian metabolism. Salvinorin A, a diterpenoid isolated from the hallucinogenic mint Salvia divinorum Epling & Játiva-M (Lamiaceae), is a potent non-nitrogenous κ-opioid receptor agonist. The metabolism of salvinorin A has still not yet been well established. Thirty fungal species were screened for the ability to metabolize salvinorin A. We observed that salvinorin A undergoes fast hydrolysis of the acetate group at carbon atom C2, resulting in formation of the pharmacologically inactive product, salvinorin B. Ex vivo experiments were also performed using organelle fractions isolated from rat liver and brain. …

Discovery Of Thienoquinolone Derivatives As Selective And Atp Non-Competitive Cdk5/P25 Inhibitors By Structure-Based Virtual Screening, Arindam Chatterjee, Stephen J. Cutler, Robert J. Doerksen, Ikhlas A. Khan, John S. Williamson

John S. Williamson

Calpain mediated cleavage of CDK5 natural precursor p35 causes a stable complex formation of CDK5/p25, which leads to hyperphosphorylation of tau. Thus inhibition of this complex is a viable target for numerous acute and chronic neurodegenerative diseases involving tau protein, including Alzheimer’s disease. Since CDK5 has the highest sequence homology with its mitotic counterpart CDK2, our primary goal was to design selective CDK5/p25 inhibitors targeting neurodegeneration. A novel structure-based virtual screening protocol comprised of e-pharmacophore models and virtual screening workflow was used to identify nine compounds from a commercial database containing 2.84 million compounds. An ATP non-competitive and selective thieno[3,2- …

Perampanel, Michael A. Rogawski

Michael A. Rogawski

No abstract provided.

Antagonism Of Triazolam Self-Administration In Rhesus Monkeys Responding Under A Progressive-Ratio Schedule: In Vivo Apparent Pa2 Analysis, Bradford D. Fischer Phd, Donna M. Platt, Sundari K. Rallapalli, Ojas A. Namjoshi, James M. Cook, James K. Rowlett

Bradford Fischer

No abstract provided.

Structural Basis And Distal Effects Of Gag Substrate Coevolution In Drug Resistance To Hiv-1 Protease, Aysegul Ozen, Kuan-Hung Lin, Nese Yilmaz, Celia Schiffer

Celia A. Schiffer

Drug resistance mutations in response to HIV-1 protease inhibitors are selected not only in the drug target but elsewhere in the viral genome, especially at the protease cleavage sites in the precursor protein Gag. To understand the molecular basis of this protease-substrate coevolution, we solved the crystal structures of drug resistant I50V/A71V HIV-1 protease with p1-p6 substrates bearing coevolved mutations. Analyses of the protease-substrate interactions reveal that compensatory coevolved mutations in the substrate do not restore interactions lost due to protease mutations, but instead establish other interactions that are not restricted to the site of mutation. Mutation of a substrate …

Structural Analysis Of Asunaprevir Resistance In Hcv Ns3/4a Protease, Djade Soumana, Akbar Ali, Celia Schiffer

Celia A. Schiffer

Asunaprevir (ASV), an isoquinoline-based competitive inhibitor targeting the hepatitis C virus (HCV) NS3/4A protease, is very potent in vivo. However, the potency is significantly compromised by the drug resistance mutations R155K and D168A. In this study three crystal structures of ASV and an analogue were determined to analyze the structural basis of drug resistance susceptibility. These structures revealed that ASV makes extensive contacts with Arg155 outside the substrate envelope. Arg155 in turn is stabilized by Asp168, and thus when either residue is mutated, the enzyme's interaction with ASV's P2* isoquinoline is disrupted. Adding a P1-P3 macrocycle to ASV enhances the …

A Sensitive Assay Using A Native Protein Substrate For Screening Hiv-1 Maturation Inhibitors Targeting The Protease Cleavage Site Between The Matrix And Capsid, Sook-Kyung Lee, Nancy Cheng, Emily Hull-Ryde, Marc Potempa, Celia Schiffer, William Janzen, Ronald Swanstrom

Celia A. Schiffer

The matrix/capsid processing site in the HIV-1 Gag precursor is likely the most sensitive target to inhibit HIV-1 replication. We have previously shown that modest incomplete processing at the site leads to a complete loss of virion infectivity. In the study presented here, a sensitive assay based on fluorescence polarization that can monitor cleavage at the MA/CA site in the context of the folded protein substrate is described. The substrate, an MA/CA fusion protein, was labeled with the fluorescein-based FlAsH (fluorescein arsenical hairpin) reagent that binds to a tetracysteine motif (CCGPCC) that was introduced within the N-terminal domain of CA. …

Drug Resistance Conferred By Mutations Outside The Active Site Through Alterations In The Dynamic And Structural Ensemble Of Hiv-1 Protease, Debra Ragland, Ellen Nalivaika, Madhavi Nalam, Kristina Prachanronarong, Hong Cao, Rajintha Bandaranayake, Yufeng Cai, Nese Yilmaz, Celia Schiffer

Celia A. Schiffer

HIV-1 protease inhibitors are part of the highly active antiretroviral therapy effectively used in the treatment of HIV infection and AIDS. Darunavir (DRV) is the most potent of these inhibitors, soliciting drug resistance only when a complex combination of mutations occur both inside and outside the protease active site. With few exceptions, the role of mutations outside the active site in conferring resistance remains largely elusive. Through a series of DRV-protease complex crystal structures, inhibition assays, and molecular dynamics simulations, we find that single and double site mutations outside the active site often associated with DRV resistance alter the structure …

Testing The Substrate-Envelope Hypothesis With Designed Pairs Of Compounds, Yang Shen, Michael Altman, Akbar Ali, Madhavi Nalam, Hong Cao, Tariq Rana, Celia Schiffer, Bruce Tidor

Celia A. Schiffer

Acquired resistance to therapeutic agents is a significant barrier to the development of clinically effective treatments for diseases in which evolution occurs on clinical time scales, frequently arising from target mutations. We previously reported a general strategy to design effective inhibitors for rapidly mutating enzyme targets, which we demonstrated for HIV-1 protease inhibition [Altman et al. J. Am. Chem. Soc. 2008, 130, 6099-6113]. Specifically, we developed a computational inverse design procedure with the added constraint that designed inhibitors bind entirely inside the substrate envelope, a consensus volume occupied by natural substrates. The rationale for the substrate-envelope constraint is that it …

Development Of A Novel Screening Strategy Designed To Discover A New Class Of Hiv Drugs, Nancy Cheng, Sook-Kyung Lee, P. Donover, Mel Reichman, Celia Schiffer, Emily Hull-Ryde, Ronald Swanstrom, William Janzen

Celia A. Schiffer

Current antiretroviral treatments target multiple pathways important for human immunodeficiency virus (HIV) multiplication, including viral entry, synthesis and integration of the DNA provirus, and the processing of viral polyprotein precursors. However, HIV is becoming increasingly resistant to these "combination therapies." Recent findings show that inhibition of HIV Gag protein cleavage into its two structural proteins, matrix (MA) and capsid (CA), has a devastating effect on viral production, revealing a potential new target class for HIV treatment. Unlike the widely used HIV protease inhibitors, this new class of inhibitor would target the substrate, not the protease enzyme itself. This approach offers …

Hiv-1 Protease-Substrate Coevolution In Nelfinavir Resistance, Madhavi Kolli, Aysegul Ozen, Nese Yilmaz, Celia Schiffer

Celia A. Schiffer

Resistance to various human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs) challenges the effectiveness of therapies in treating HIV-1-infected individuals and AIDS patients. The virus accumulates mutations within the protease (PR) that render the PIs less potent. Occasionally, Gag sequences also coevolve with mutations at PR cleavage sites contributing to drug resistance. In this study, we investigated the structural basis of coevolution of the p1-p6 cleavage site with the nelfinavir (NFV) resistance D30N/N88D protease mutations by determining crystal structures of wild-type and NFV-resistant HIV-1 protease in complex with p1-p6 substrate peptide variants with L449F and/or S451N. Alterations of residue …

Substrate Envelope-Designed Potent Hiv-1 Protease Inhibitors To Avoid Drug Resistance, Madhavi Nalam, Akbar Ali, G. S. Kiran Kumar Reddy, Hong Cao, Saima Anjum, Michael Altman, Nese Yilmaz, Bruce Tidor, Tariq Rana, Celia Schiffer

Celia A. Schiffer

The rapid evolution of HIV under selective drug pressure has led to multidrug resistant (MDR) strains that evade standard therapies. We designed highly potent HIV-1 protease inhibitors (PIs) using the substrate envelope model, which confines inhibitors within the consensus volume of natural substrates, providing inhibitors less susceptible to resistance because a mutation affecting such inhibitors will simultaneously affect viral substrate processing. The designed PIs share a common chemical scaffold but utilize various moieties that optimally fill the substrate envelope, as confirmed by crystal structures. The designed PIs retain robust binding to MDR protease variants and display exceptional antiviral potencies against …

Role Of Gluk1 Kainate Receptors In Seizures, Epileptic Discharges, And Epileptogenesis, Brita Fritsch, Janine Reis, Maciej Gasior, Rafal M. Kaminski, Michael A. Rogawski

Michael A. Rogawski

Kainate receptors containing the GluK1 subunit have an impact on excitatory and inhibitory neurotransmission in brain regions, such as the amygdala and hippocampus, which are relevant to seizures and epilepsy. Here we used 2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl) propanoic acid (ATPA), a potent and selective agonist of kainate receptors that include the GluK1 subunit, in conjunction with mice deficient in GluK1 and GluK2 kainate receptor subunits to assess the role of GluK1 kainate receptors in provoking seizures and in kindling epileptogenesis. We found that systemic ATPA, acting specifically via GluK1 kainate receptors, causes locomotor arrest and forelimb extension (a unique behavioral characteristic of GluK1 …

Role Of Gluk1 Kainate Receptors In Seizures, Epileptic Discharges, And Epileptogenesis, Brita Fritsch, Janine Reis, Maciej Gasior, Rafal M. Kaminski, Michael A. Rogawski

Michael A. Rogawski

Kainate receptors containing the GluK1 subunit have an impact on excitatory and inhibitory neurotransmission in brain regions, such as the amygdala and hippocampus, which are relevant to seizures and epilepsy. Here we used 2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl) propanoic acid (ATPA), a potent and selective agonist of kainate receptors that include the GluK1 subunit, in conjunction with mice deficient in GluK1 and GluK2 kainate receptor subunits to assess the role of GluK1 kainate receptors in provoking seizures and in kindling epileptogenesis. We found that systemic ATPA, acting specifically via GluK1 kainate receptors, causes locomotor arrest and forelimb extension (a unique behavioral characteristic of GluK1 …

Tetramethylenedisulfotetramine, Christopher N. Banks, Dongren Yang, Pamela J. Lein, Michael A. Rogawski

Michael A. Rogawski

Tetramethylenedisulfotetramine (2,6-dithia-1,3,5,7-tetraazadamantane,2,2,6,6-tetraoxide, TETS) is a highly toxic heteroadamantane rodenticide. It is an odorless, tasteless,white crystalline powder that is slightly soluble in water (0.25 mg ml-1), dimethylsulfoxide and acetone. It was originally synthesized in 1933 as a resinous condensation product of sulfamide and formaldehyde and used commercially in pillows and upholstery as animpregnating stiffening and anti mold agent. However, in 1950, a massive poisoning of German workers in the furniture manufacturing industry was linked to ‘Crinex’ wool, which contained TETS as a by product of processing.

Prolactin And Fmri Response To Skf38393 In The Baboon, Brad D. Miller, Lauren A. Marks, Jonathan M. Koller, Blake J. Newman, G Larry Bretthorst, Kevin J. Black

Kevin J. Black, MD

Background: This study’s goal was to provide dose-response data for a dopamine agonist in the baboon using standard methods (replicate measurements at each dose, across a range of doses), as a standard against which to subsequently validate a novel pharmacological MRI (phMRI) method. Dependent variables were functional MRI (fMRI) data from brain regions selected a priori, and systemic prolactin release. Necessary first steps included estimating the magnitude and time course of prolactin response to anesthesia alone and to various doses of agonist. These first steps (“time course studies”) were performed with three agonists, and the results were used to select …

Seizure Protection By Intrapulmonary Delivery Of Midazolam In Mice, Ashish Dhir, Dorota Zolkowska, Michael A. Rogawski

Michael A. Rogawski

The lung provides a portal of entry that could be used to rapidly deliver anticonvulsant substances to the brain to treat seizures. In the present study, we demonstrate that midazolam, a water-soluble anticonvulsant benzodiazepine, confers potent seizure protection when administered via the intrapulmonary route. High dose (100 mg/kg) intraperitoneal midazolam induced loss-of-righting reflex in mice. Lower doses of midazolam (100–1000 μg/kg) when administered intraperitoneally did not induce loss-of-righting reflex but protected animals against pentylenetetrazol (PTZ)-induced seizures. Intrapulmonary administration of midazolam via a tracheal cannula protected against intraperitoneal PTZ seizures at lower doses. The minimal intraperitoneal and intravenous doses of midazolam …

Long-Lasting Attenuation Of Amygdala-Kindled Seizures After Convection-Enhanced Delivery Of Botulinum Neurotoxins A And B Into The Amygdala In Rats, Maciej Gasior, Rebecca Tang, Michael A. Rogawski

Michael A. Rogawski

Botulinum neurotoxins (BoNTs) are well recognized to cause potent, selective and long-lasting neuroparalytic actions by blocking cholinergic neurotransmission to muscles and glands. There is evidence that BoNT isoforms can also inhibit neurotransmission in the brain. Here we examined whether locally delivered BoNT/A and BoNT/B can attenuate kindling measures in amygdala-kindled rats. Male rats were implanted with a combination infusion cannula-stimulating electrode assembly into the right basolateral amygdala. Fully-kindled animals received a single infusion of vehicle or BoNT/A or BoNT/B at doses of 1, 3.2, or 10 ng over a 20-min period by convection enhanced delivery (CED). Electrographic (EEG) and behavioral …

Issues Related To Development Of New Antiseizure Treatments, Karen S. Wilcox, Tracy Dixon-Salazar, Graeme J. Sills, Elinor Ben-Menachem, H. Steve White, Roger J. Porter, Marc A. Dichter, Solomon L. Moshe, Jeffrey L. Noebels, Michael D. Privitera, Michael A. Rogawski

Michael A. Rogawski

This report represents a summary of the discussions led by the antiseizure treatment working group of the International League Against Epilepsy (ILAE)/American Epilepsy Society (AES) Working Groups joint meeting in London (London Meeting). We review here what is currently known about the pharmacologic characteristics of current models of refractory seizures, both for adult and pediatric epilepsy. In addition, we address how the National Institute of Neurological Disorders and Stroke (NINDS)-funded Anticonvulsant Screening Program (ASP) is evolving to incorporate appropriate animal models in the search for molecules that might be sufficiently novel to warrant further pharmacologic development. We also briefly address …

The Intrinsic Severity Hypothesis Of Pharmacoresistance To Antiepileptic Drugs, Michael Rogawski

Michael A. Rogawski

Pharmacoresistance to antiepileptic drugs (AEDs) is a barrier to seizure freedom for many persons with epilepsy. For nearly two decades, pharmacoresistance has been framed in terms of factors affecting the access of AEDs to their molecular targets in the brain or the actions of the drugs on these targets. Shortcomings in this prevailing view led to the formulation of the intrinsic severity hypothesis of pharmacoresistance to AEDs, which is based on the recognition that there are neurobiologic factors that confer phenotypic variation among individuals with etiologically similar forms of epilepsy and postulates that more severe epilepsy is more difficult to …

Pyocyanin-Induced Toxicity In A549 Respiratory Cells Is Causally Linked To Oxidative Stress, Lee Gloyne, Gary Grant, Anthony Perkins, Katie Powell, Catherine Mcdermott, Peter Johnson, Gregory Anderson, Milton Kiefel, Shailendra Anoopkumar-Dukie

Catherine M. McDermott

Pyocyanin, a virulence factor produced by Pseudomonas aeruginosa, has many damaging effects on mammalian cells. Several lines of evidence suggest that this damage is primarily mediated by its ability to generate ROS and deplete host antioxidant defence mechanisms. However, a causal role for oxidative stress has not yet been demonstrated conclusively. Parallel measures of ROS production, antioxidant levels and cytotoxicity provide convincing evidence that pyocyanin-induced cytotoxicity in A549 respiratory cells is mediated by acute ROS production and subsequent oxidative stress. Pyocyanin increased ROS levels in A549 cells as measured by the fluorescent H2O2 probes Amplex Red and DCFH-DA. These effects …

Dual Recognition Of The Ribosome And The Signal Recognition Particle By The Srp Receptor During Protein Targeting To The Endoplasmic Reticulum, Elisabet C. Mandon, Ying Jiang, Reid Gilmore

Elisabet Mandon

We have analyzed the interactions between the signal recognition particle (SRP), the SRP receptor (SR), and the ribosome using GTPase assays, biosensor experiments, and ribosome binding assays. Possible mechanisms that could contribute to an enhanced affinity between the SR and the SRP-ribosome nascent chain complex to promote protein translocation under physiological ionic strength conditions have been explored. Ribosomes or 60S large ribosomal subunits activate the GTPase cycle of SRP54 and SRalpha by providing a platform for assembly of the SRP-SR complex. Biosensor experiments revealed high-affinity, saturable binding of ribosomes or large ribosomal subunits to the SR. Remarkably, the SR has …

Erectogenic Effects Of Clerodendron Capitatum: Involvement Of Phosphodiesterase Type-5 Inhibition, Dr Syam Mohan

Syam Mohan

No abstract provided.

Clausena Excavata Burm. F. (Rutaceae): A Review Of Its Traditional Uses, Pharmacological And Phytochemical Properties., Dr Syam Mohan

Syam Mohan

The present review describes the morphological, traditional, phytochemical and pharmacological aspects of Clausena excavata (Burm. f., Rutaceae). The plant grows wild in the tropical and subtropical parts of Asia and represents one of the richest sources of medicinal natural products. It is intensively used currently in traditional medicine for treatment of different illnesses. One part or a mixture of two or more parts of the plant in the form of powder or liquid doze is usually given to the patient. Phytochemically, many pure compounds from several secondary metabolite groups of C. excavata have been isolated from different parts of the …

Chloroform Fraction Of Centratherum Anthelminticum (L.) Seed Inhibits Tumor Necrosis Factor Alpha And Exhibits Pleotropic Bioactivities: Inhibitory Role In Human Tumor Cells, Dr Syam Mohan

Syam Mohan

We investigated the antioxidant potential, cytotoxic effect, and TNF-α inhibition activity with NF-κB activation response in a chloroformfraction of Centratherum anthelminticum seeds (CACF). The antioxidant property of CACF was evaluated with DPPH, ORAC, and FRAP assays, which demonstrated significant antioxidant activity. The cytotoxicity of CACF was tested using theMTT assay; CACF effective inhibitory concentrations (IC50) for A549, PC-3, MCF-7, and WRL-68 cells were 31.42 ± 5.4, 22.61 ± 1.7, 8.1±0.9, and 54.93±8.3 μg/mL, respectively. CACF effectively and dose-dependently inhibited TNF-α release, in vitro and in vivo. CACF inhibited TNF-α secretion in stimulated RAW264.7macrophage supernatants with an IC50 of 0.012 μg/mL, …

In Vitro Anti-Inflammatory, Cytotoxic And Antioxidant Activities Of Boesenbergin A, A Chalcone Isolated From Boesenbergia Rotunda (L.) (Fingerroot), Dr Syam Mohan

Syam Mohan

The current in vitro study was designed to investigate the anti-inflammatory, cytotoxic and antioxidant activities of boesenbergin A (BA), a chalcone derivative of known structure isolated from Boesenbergia rotunda. Human hepatocellular carcinoma (HepG2), colon adenocarcinoma (HT-29), non-small cell lung cancer (A549), prostate adenocarcinoma (PC3), and normal hepatic cells (WRL-68) were used to evaluate the cytotoxicity of BA using the MTT assay. The antioxidant activity of BA was assessed by the ORAC assay and compared to quercetin as a standard reference antioxidant. ORAC results are reported as the equivalent concentration of Trolox that produces the same level of antioxidant activity as …

Synthesis Of Chalcones With Anticancer Activities., Dr Syam Mohan

Syam Mohan

Several chalcones were synthesized and their in vitro cytotoxicity against various human cell lines, including human breast adenocarcinoma cell line MCF-7, human lung adenocarcinoma cell line A549, human prostate cancer cell line PC3, human adenocarcinoma cell line HT-29 (colorectal cancer) and human normal liver cell line WRL-68 was evaluated. Most of the compounds being active cytotoxic agents, four of them with minimal IC50 values were chosen and studied in detail with MCF-7 cells. The compounds 1, 5, 23, and 25 were capable in eliciting apoptosis in MCF-7 cells as shown by multiparameter cytotoxicity assay and caspase-3/7, -8, and -9 activities …