Investigation Of Pharmacology Research Articles

Comprehensive investigation of network pharmacology, computational modeling, and pharmacokinetic assessment to evaluate the efficacy of flavonoids in rheumatoid arthritis.

Rheumatoid arthritis is a chronic autoimmune disease characterized by inflammation and joint damage, imposing a significant burden on affected individuals worldwide. Flavonoids, a class of natural compounds abundant in various plant-based foods, have shown promising anti-inflammatory and immunomodulatory effects, suggesting their potential as therapeutic agents for RA. In this study, we conducted a comprehensive investigation of identified LCMS compounds utilizing network pharmacology, computational modeling, in silico approaches, and pharmacokinetic assessment to evaluate the efficacy of flavonoids in RA treatment. The study identified 5 flavonoid structures with common targets via LCMS and Integration of network pharmacology approaches enabled a comprehensive evaluation of the pharmacological profile of flavonoids in the context of RA treatment, guiding the selection of promising candidates for further experimental validation and clinical development. The top 10 targets were AKT1, PI3KR1, CDK2, EGFR, CDK6, NOS2, FLT3, ALOX5, CCNB1, and PTPRS via PPI network. The investigation emphasized several pathways, including the AGE-RAGE signaling pathway, resistance to EGFR tyrosine kinase inhibitors, the PI3K-AKT signaling network, and the Rap 1 signaling pathway. In silico studies estimated binding affinities that ranged from - 7.0 to - 10.0 kcal/mol. Schaftoside and Vitexin showed no toxicity in computational approach and found suitable for further investigations. Overall, our study underscores the potential of flavonoids as therapeutic agents for RA and highlights the utility of integrative approaches combining network pharmacology, computational modeling, in silico methods, and pharmacokinetic assessment in drug discovery and development processes.

Exploring the mechanism of agarwood moxa smoke in treating sleep disorders based on GC-MS and network pharmacology.

Agarwood moxibustion is a folk therapy developed by individuals of the Li nationality in China. There is evidence that agarwood moxa smoke (AMS) generated during agarwood moxibustion therapy can treat sleep disorders via traditional Chinese medicines' multiple target and pathway characteristics. However, the specific components and mechanisms involved have yet to be explored. GC-MS (Gas Chromatography-Mass Spectrometry) and network pharmacology were used to investigate AMS's molecular basis and mechanism in treating sleep deprivation. GC-MS was used to determine the chemical composition of AMS; component target information was collected from TCMSP (Traditional Chinese Medicine Systems Pharmacology), PubChem (Public Chemical Database), GeneCards (Human Gene Database), and DisGeNet (Database of Genes and Diseases) were used to identify disease targets, and JVenn (Joint Venn) was used to identify the common targets of AMS and sleep disorders. STRING was used to construct a protein interaction network, Cytoscape 3.9.1 was used to build a multilevel network diagram of the "core components-efficacy targets-action pathways," the targets were imported into Metascape and DAVID for GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses and Autodock was used for molecular docking. This research used a network pharmacology methodology to investigate the therapeutic potential of Agarwood Moxa Smoke (AMS) in treating sleep problems. Examining the target genes and chemical constituents of AMS offers insights into the molecular processes and targets of the disease. Nine active ingredients comprising anti-inflammatory substances and antioxidants, such as caryophyllene and p-cymene, found seven sleep-regulating signaling pathways and eight targets linked to sleep disorders. GC-MS was used to identify the 94 active ingredients in AMS, and the active ingredients had strong binding with the key targets. Key findings included active components with known medicinal properties, such as p-cymene, eucalyptol, and caryophyllene. An investigation of network pharmacology revealed seven signaling pathways for sleep regulation and eight targets linked to sleep disorders, shedding light on AMS's effectiveness in enhancing sleep quality. AMS may alleviate sleep disorders by modulating cellular and synaptic signaling, controlling hormone and neurotransmitter pathways, etc. Understanding AMS's material basis and mechanism of action provides a foundation for future research on treating sleep disorders with AMS. According to the study, Agarwood Moxa Smoke (AMS) may improve sleep quality by modifying cellular and synaptic signaling pathways for those who suffer from sleep problems. This might lead to the development of innovative therapies with fewer side effects.

A microphysiological system for parallelized morphological and electrophysiological read-out of 3D neuronal cell culture.

Three-dimensional in vitro models in microfluidic systems are promising tools for studying cell biology, with complex models using multiple cell types combined with high resolution imaging. Neuronal models demand electrical readout of the activity of networks of single neurons, yet classical planar microelectrode arrays struggle to capture extracellular action potentials when neural soma are suspended distant from the microelectrodes. This study introduces sophisticated microfluidic microelectrode arrays, specifically tailored for electrophysiology of 3D neuronal cultures. Using multilayer photolithography of permanent epoxy photoresists, we developed devices having 12 independent culture modules in a convenient format. Each module has two adjacent compartments for hydrogel-based 3D cell culture, with tunnels allowing projection of neurites between compartments. Microelectrodes integrated in the tunnels record action potentials as they pass between the compartments. Mesh ceilings separate the compartments from overlying wells, allowing for simple cell seeding and later nutrient, gas and waste exchange and application of test substances. Using these devices, we have demonstrated 3D neuronal culture, including electrophysiological recording and live imaging. This microphysiological platform will enable high-throughput investigation of neuronal networks for investigation of neurological disorders, neural pharmacology and basic neuroscience. Further models could include cocultures representing multiple brain regions or innervation models of other organs.

Inhibition of temperature-sensitive TRPV3 channel by two natural isochlorogenic acid isomers for alleviation of dermatitis and chronic pruritus

Genetic gain-of-function mutations of warm temperature-sensitive transient receptor potential vanilloid 3 (TRPV3) channel cause Olmsted syndrome characterized by severe itching and keratoderma, indicating that pharmacological inhibition of TRPV3 may hold promise for therapy of chronic pruritus and skin diseases. However, currently available TRPV3 tool inhibitors are either nonselective or less potent, thus impeding the validation of TRPV3 as therapeutic target. Using whole-cell patch-clamp and single-channel recordings, we report the identification of two natural dicaffeoylquinic acid isomers isochlorogenic acid A (IAA) and isochlorogenic acid B (IAB) that selectively inhibit TRPV3 currents with IC50 values of 2.7 ± 1.3 and 0.9 ± 0.3 μmol/L, respectively, and reduce the channel open probability to 3.7 ± 1.2% and 3.2 ± 1.1% from 26.9 ± 5.5%, respectively. In vivo evaluation confirms that both IAA and IAB significantly reverse the ear swelling of dermatitis and chronic pruritus. Furthermore, the isomer IAB is able to rescue the keratinocyte death induced by TRPV3 agonist carvacrol. Molecular docking combined with site-directed mutations reveals two residues T636 and F666 critical for the binding of the two isomers. Taken together, our identification of isochlorogenic acids A and B that act as specific TRPV3 channel inhibitors and gating modifiers not only provides an essential pharmacological tool for further investigation of the channel pharmacology and pathology, but also holds developmental potential for treatment of dermatitis and chronic pruritus.

Chemogenomics Systems Pharmacology Mapping of Potential Drug Targets for Treatment of Traumatic Brain Injury.

Traumatic brain injury (TBI) is associated with high mortality and morbidity. Though the death rate of initial trauma has dramatically decreased, no drug has been developed to effectively limit the progression of the secondary injury caused by TBI. TBI appears to be a predisposing risk factor for Alzheimer's disease (AD), whereas the molecular mechanisms remain unknown. In this study, we have conducted a research investigation of computational chemogenomics systems pharmacology (CSP) to identify potential drug targets for TBI treatment. TBI-induced transcriptional profiles were compared with those induced by genetic or chemical perturbations, including drugs in clinical trials for TBI treatment. The protein-protein interaction network of these predicted targets were then generated for further analyses. Some protein targets when perturbed, exhibit inverse transcriptional profiles in comparison with the profiles induced by TBI, and they were recognized as potential therapeutic targets for TBI. Drugs acting on these targets are predicted to have the potential for TBI treatment if they can reverse the TBI-induced transcriptional profiles that lead to secondary injury. In particular, our results indicated that TRPV4, NEUROD1, and HPRT1 were among the top therapeutic target candidates for TBI, which are congruent with literature reports. Our analyses also suggested the strong associations between TBI and AD, as perturbations on AD-related genes, such as APOE, APP, PSEN1, and MAPT, can induce similar gene expression patterns as those of TBI. To the best of our knowledge, this is the first CSP-based gene expression profile analyses for predicting TBI-related drug targets, and the findings could be used to guide the design of new drugs targeting the secondary injury caused by TBI.

Site-Directed Unnatural Amino Acid Mutagenesis to Investigate Potassium Channel Pharmacology in Xenopus laevis Oocytes.

Unnatural amino acid mutagenesis is a useful tool enabling detailed investigation of ion channel structure-function relationships and pharmacology. Methods have been developed to apply this technique to different heterologous systems for electrophysiological studies, with each system offering unique advantages and limitations. Synthesis of aminoacylated-tRNA followed by injection into Xenopus laevis oocytes is beneficial because it allows for the incorporation of a wide range of unnatural sidechains, including amino acids with subtle structural differences. Here, we describe a protocol for unnatural amino acid mutagenesis implemented in our lab to study the pharmacology of KCNQ voltage-gated potassium channel opener compounds. This protocol should be applicable to other ion channels and receptor types amenable for functional studies in Xenopus laevis oocytes.

Oxaliplatin in the era of personalized medicine: from mechanistic studies to clinical efficacy.

Oxaliplatin is a third-generation platinum compound approved for clinical use relatively recently as compared to other drugs of the same class. Its main cellular target is DNA, where similarly to cisplatin and carboplatin it forms cross-links. However, due to a unique indication for colorectal cancer, synergistic interaction with fluoropyrimidines and peculiar toxicity profile, oxaliplatin is different from those compounds. Multiple lines of evidence indicate differences in transport and metabolism, consequences of DNA platination, as well as DNA repair and transduction of DNA damage. Here, we explore the preclinical features that may explain the unique properties of oxaliplatin in the clinics. Among them, the capability to accumulate in tumor cells via organic cation transporters, to kill KRAS mutant cells and to activate immunogenic cell death appears helpful to explain in part its clinical behavior. The continuous investigation of the molecular pharmacology of oxaliplatin is expected to provide clues to the definitions of predictors of drug activity and toxicity to translate to the clinical setting.

<i>Belamcanda chinensis</i> (l.) Dc: Ethnopharmacology, phytochemistryand pharmacology of an important traditional Chinese medicine

Background: Belamcanda chinensis (L.) DC (Iridaceae), a widely used traditional Chinese medicine known as She Gan (Chinese: 射干), is a flowering perennial herb native to East Asia. For thousands of years in China, the rhizome of Belamcanda chinensis has been used to treat inflammation, oxyhepatitis, mumps, acute mastitis, and asthma, as well as throat disorders such as cough, tonsillitis and pharyngitis. Belamcanda chinensis is now listed in the Pharmacopoeia of the People’s Republic of China. The present paper reviews the advancements in the investigation of botany, ethnopharmacology, phytochemistry, pharmacology and toxicology of Belamcanda chinensis . Materials and Methods: Information on Belamcanda chinensis was collected from scientific journals, books, theses and reports via library and electronic search (PubMed, CNKI, Elsevier, ACS, Google Scholar, Baidu Scholar,Web of Science and Science Direct). Results: A number of chemical compounds have been isolated from Belamcanda chinensis , and the major isolated compounds have been identified as isoflavonoids, flavonoids and iridal-type triterpenoids. Among these active compounds, the effects of tectoridin and tectorigenin have been widely investigated. The primary active components in Belamcanda chinensis possess a wide range of pharmacological activities, including anti-inflammatory, anti-oxidative, anti-tumour, anti-alcohol injury, cardiovascular and oestrogenic activities. Conclusions: As an important traditional Chinese medicine, Belamcanda chinensis has been demonstrated to have marked bioactivity, especially in the respiratory system and as an oestrogenic and hepatoprotective agent. This activity is related to its traditional use and provides opportunities for the development of novel drugs and therapeutic products for various diseases. However, the toxicity of Belamcanda chinensis will require further study, and more attention should be devoted to its better utilization. Keywords: Belamcanda chinensis ; Ethnopharmacology; Phytochemistry; Pharmacology; Toxicology

Abstract 95: Pharmacological Characterization of Adenosine Effects on Spontaneously Beating Human-IPSC-Derived Cardiomyocytes

Purified human-Induced Pluripotent Stem Cell-derived cardiomyocytes (hIPSC-CMs: iCells®, Cellular Dynamics) form electrically coupled, spontaneously beating cell monolayers (syncytia) upon plating and continuous culture. In this study, we investigate the pharmacology of the hIPSC-CM adenosine (ADO) response via the use of selective A1 and A2A-receptor antagonists and equilibrative nucleoside transporter type-1 (ENT1) inhibitors. After a 14-day culture in 96-well impedance electrode-plates (ACEA Biosciences), the spontaneous iCell beating rates are highly stable from well to well, with a mean beat period of 1.7 sec at 37°C, and a coefficient of variation (CV) < 1% . Extracellularly applied ADO inhibits the spontaneous beating rate of iCells with an IC 50 = 2.2 μM, and a saturation value of near 50% inhibition. ADO also destabilizes the beat period (CV EC 50 = 1.2 μM) with a maximum CV of 20% at saturating ADO concentrations. The ADO IC 50 is shifted to 248 μM upon pre-incubation of the iCells with 1 μM of an A1-selective antagonist DPCPX (A1 K i =3.9 nM), but not the A2A-selective antagonist ZM241385 (A2A K i =1nM). The duration of the depressive effect of ADO on beating rate is transient, even at super-saturating ADO concentrations, and depends on the well ADO concentration. The ENT1 inhibitor Draflazine (ENT1 pK i =9.5) pre-applied at 0.1 μM increases ADO sensitivity by 4-fold one hour after ADO application. Moreover, at any given ADO concentration, the duration of beating rate depression can be prolonged in a concentration-dependent manner by ENT1 inhibitors, with the prolongation-response curve nearly matching the ENT1 IC 50 s for tested ENT1 inhibitors (Draflazine, NBTI, Dilazep, and Dipyridamole). These findings suggest that the pool of ADO in the test well is cleared by uptake via endogenous ENT1 and support the role of equilibrative ADO uptake in limiting the duration of action of ADO on A1 receptors in cardiomyocytes. We are extending our investigation to the downstream target of A1 receptor activity, and the putative role of IK ACH/ADO as the underlying mechanism of beat rate slowing and irregularity. In conclusion, the hIPSC-CM model provides a useful model for investigation of ADO pharmacology of the heart.

Investigation of the novel pharmacology of Neuropeptide Y (NPY) receptor dimers constrained by bimolecular fluorescence complementation (BiFC)

Dimerisation of GPCRs potentially influences their pharmacology via binding site cooperativity or modified signalling. We have used bimolecular fluorescence complementation (BiFC; Kilpatrick et al. (2012) Methods Mol Biol 897) to constrain Neuropeptide Y (NPY) Y1 receptor (Y1R) homo and heterodimers of known composition. Using quantitative platereader imaging we measured the internalisation of BiFC receptor dimers simultaneously with endocytosis of SNAP tagged Y1R protomer to compare the pharmacology of Y1/Y1, Y1/Y4 or Y1/Y5 BiFC dimers.Y1/Y1 and Y1/Y4 BiFC dimers internalised in response to NPY or PP (Y1/Y4), with potencies comparable to individually expressed YR subtypes. Endocytosis of Y1/Y1 or Y1/Y4 dimers to NPY was also inhibited by the Y1 antagonist BIBO3304, with expected pKb values ((8.2–8.5) from NPY concentration‐response curve shifts). However, the Y5 selective agonist PP(1–17)(Ala31, Aib32) NPY(18– 36) showed reduced potency for constrained Y1/Y5 BiFC dimers, compared to Y5‐GFP internalisation. BIBO3304 demonstrated a lower apparent affinity (pKb 7.4 ± 0.1) for Y1/Y5 BiFC dimers compared to the SNAP‐Y1 sub‐population (pKb 8.2 ± 0.4). This suggests an interaction between Y1 and Y5 orthosteric binding sites of Y1/Y5 BiFC dimers, with implications for selective targeting of this dimer as a mediator of central NPY appetite responses. LK is supported by the British Pharmacological Society.

Investigation of Pharmacodynamics, Pharmacology, and Toxicology of Domestic Human Prourokinase

The comparison of the effect of fibrinolytic activity of recombinant human prourokinase (rhpro-UK) and urokinase(UK) with rabbits indicated rhpro-UK and UK all decreased resolution time of globular proteins, and the affect of rhpro-UK on parameter of fibrinolysis of rabbits was less than UK. The solution of thrombin of rhpro-UK in vitro was increased with dosage of rhpro-UK, and when rhpro-UK was compared with isodose UK, the difference is significant. Both rhpro-UK and UK all was marked solution of thrombin from Chinese piglets, and it were not evident effect on fibrinogen, plasminogen, and a2-antiplasmin of the piglets. The affect of rhpro-UK on bleeding time, clotting time, bleeding amount of unit time was less than UK. It indicated that the side effect of rhpro-UK was distinguished less than UK. The investigation of pharmacology of ileums of mice, rats, dogs, and guinea pigs indicated that rhpro-UK was not marked affect on behavior, state, central nervous system, cardiovascular system, respiratory system, and digestive system of the tested animals. But tested dogs were bleeding at location of operation, and the blood of the animal was heparinized. The studis of toxicology of rhpro-UK indicated that rhpro-UK was median lethal dose of 97.5 mg/kg in mice. When The Beagle dogs was administed rhpro-UK of 2, 8, 28 mg/kg, the toxic reaction was not observed, except for temporal hyperemia of gum, extend of clotting time, increasing of total cholerythrin, total proteins, albumin of the dogs, the direct damage of organs for the medicine was not observed in examination of pathology in the dosages of 8 and 28 mg/kg, any toxic reaction was not observed in dosage of 2 mg/kg. The special toxic experiments proved that rhpro-UK was not of mutagenesis and teratogenesis.

Disparate effects of pramipexole on locomotor activity and sensorimotor gating in Sprague–Dawley rats

Prepulse inhibition (PPI) of acoustic startle and locomotor activity are both widely studied in the preclinical development of dopaminergic agents, including those acting at D3 dopamine receptors. In mice, the dopamine D3 receptor-preferential agonist pramipexole (PPX) alters locomotor activity in a biphasic manner at doses that have no effect on PPI. The present study examined the time-course of PPX effects on locomotion and PPI in rats. In adult male Sprague–Dawley rats, PPX (0, 0.1, 0.3, 1.0mg/kg) was injected prior to measurement of locomotor activity for 90min in photobeam chambers. Based on disparate early vs. late effects of PPX on locomotion, the effects of PPX (0 vs. 0.3mg/kg) on PPI were tested 20 and 80min after injection. All doses of PPX decreased locomotor activity for 30min compared to vehicle, and the higher doses stimulated hyperlocomotion later in the session; the late hyperlocomotion, but not the early hypolocomotion, was blocked by the D2-selective antagonist, L741626 (1.0mg/kg sc). In contrast to its locomotor effects, PPX caused a similar reduction in PPI at 20 and 80min after administration. These findings suggest both a temporal and pharmacological dissociation between PPX effects on locomotor activity and PPI; these two behavioral measures contribute non-redundant information to the investigation of D3-related behavioral pharmacology.

Importance of Astavarga plants in traditional systems of medicine in Garhwal, Indian Himalaya

This study documents the medicinal uses of Astavarga, a group of eight medicinal herbs, used in traditional medical knowledge (TMK) of the Himalaya region and in the traditional medical system (TMS) in India. Field surveys were conducted during 2006–2008 to collect data on the availability and uses of Astavarga across 21 diverse localities. During the surveys, information was collected on types of ailments treated and plant parts used in different therapies in TMK using semi-structured questionnaires. Overall, information was gathered from 92 informants in the study area. These herbs are mostly used to treat sexual problems, physical disability, respiratory problems, different types of pain, fever and urinary problems, as well as anti-ageing agents. Information on medicinal properties of these plants was also collected from secondary sources, i.e. the traditional medical system (Ayurveda) and through a literature survey. This revealed that Astavarga in TMS is mostly used to treat sexual disorders, physical weakness, to strengthen the immune system, body pain and as a tonic. Analysis of TMK in the Himalaya reveals some new medicinal properties of Astavarga while the literature survey indicates that some of the plants, viz. Habenaria and Malaxis species, are not explored so far for their chemical constituents and biological activity. New medicinal uses, as recorded by this study, will provide insights for further investigation of pharmacology and phytochemical constituents of these species.

Human Airway Contraction and Formoterol-Induced Relaxation Is Determined by Ca2+ Oscillations and Ca2+ Sensitivity

The etiology of airway hyperresponsiveness associated with asthma requires an understanding of the regulatory mechanisms mediating human airway smooth muscle cell (SMC) contraction. The objective of this study was to determine how human airway SMC contraction (induced by histamine) and relaxation (induced by formoterol) are regulated by Ca(2+) oscillations and Ca(2+) sensitivity. The responses of human small airways and their associated SMCs were studied in human lung slices cut from agarose-inflated lungs. Airway contraction was measured with phase-contrast video microscopy. Ca(2+) signaling and Ca(2+) sensitivity of airway SMCs were measured with two-photon fluorescence microscopy and Ca(2+)-permeabilized lung slices. The agonist histamine induced contraction of human small airways by stimulating both an increase in intracellular Ca(2+) concentration in the SMCs in the form of oscillatory Ca(2+) waves and an increase in Ca(2+) sensitivity. The frequency of the Ca(2+) oscillations increased with histamine concentration, and correlated with increased contraction. Formoterol induced airway relaxation at low concentrations by initially decreasing SMC Ca(2+) sensitivity. At higher concentrations, formoterol additionally slowed or inhibited the Ca(2+) oscillations of the SMCs to relax the airways. The action of formoterol was only slowly reversed. Human lung slices provide a powerful experimental assay for the investigation of small airway physiology and pharmacology. Histamine induces contraction by simultaneously increasing SMC Ca(2+) signaling and Ca(2+) sensitivity. Formoterol induces long-lasting relaxation by initially reducing the Ca(2+) sensitivity and, subsequently, the frequency of the Ca(2+) oscillations of the airway SMCs.

Respiratory and Sleep Effects of Remifentanil in Volunteers with Moderate Obstructive Sleep Apnea

There is concern that opioid-based analgesia will worsen sleep-related respiratory insufficiency in patients with obstructive sleep apnea (OSA), resulting in serious morbidity or mortality. However, there are no studies that directly address the merit of this concern. Consequently, the authors designed this study as the first prospective, double-blind, placebo-controlled investigation of opioid pharmacology in patients with documented OSA. Patients (n = 19) with moderate OSA documented by polysomnography (sleep study) were randomized to undergo an additional sleep study while receiving either a saline infusion or a remifentanil infusion (0.075 microg x kg x h). Sleep stages, apneas, hypopneas, and arterial hemoglobin oxygen saturation were continually recorded during saline or remifentanil infusion, and were compared with values obtained during the patients' earlier sleep study. Saline infusion had no effect on sleep or respiratory variables. In contrast, remifentanil increased Stage 1 sleep, markedly decreased rapid eye movement sleep, increased arousals from sleep, and decreased sleep efficiency. Remifentanil actually decreased the number of obstructive apneas, but markedly increased the number of central apneas. Arterial hemoglobin oxygen saturation was also significantly lower in OSA patients receiving remifentanil. The decrease in obstructive apneas likely resulted from the marked decrease in rapid eye movement sleep caused by remifentanil. Despite fewer obstructions, OSA was worse during remifentanil infusion because of a marked increase in the number of central apneas. These data suggest that caution is warranted when administering opioids to subjects with moderate OSA, but that the primary risk may be central apnea, not obstructive apnea.

Pharmacological Characterization of Membrane-Expressed Human Trace Amine-Associated Receptor 1 (TAAR1) by a Bioluminescence Resonance Energy Transfer cAMP Biosensor

Trace amines are neurotransmitters whose role in regulating invertebrate physiology has been appreciated for many decades. Recent studies indicate that trace amines may also play a role in mammalian physiology by binding to a novel family of G protein-coupled receptors (GPCRs) that are found throughout the central nervous system. A major obstacle impeding the careful pharmacological characterization of trace amine associated receptors (TAARs) is their extremely poor membrane expression in model cell systems, and a molecular basis for this phenomenon has not been determined. In the present study, we show that the addition of an asparagine-linked glycosylation site to the N terminus of the human trace amine associated receptor 1 (TAAR1) is sufficient to enable its plasma membrane expression, and thus its pharmacological characterization with a novel cAMP EPAC (exchange protein directly activated by cAMP) protein based bioluminescence resonance energy transfer (BRET) biosensor. We applied this novel cAMP BRET biosensor to evaluate the activity of putative TAAR1 ligands. This study represents the first comprehensive investigation of the membrane-expressed human TAAR1 pharmacology. Our strategy to express TAARs and to identify their ligands using a cAMP BRET assay could provide a foundation for characterizing the functional role of trace amines in vivo and suggests a strategy to apply to groups of poorly expressing GPCRs that have remained difficult to investigate in model systems.

Propranolol blocks chronic risperidone treatment-induced enhancement of spatial working memory performance of rats in a delayed matching-to-place water maze task

Atypical antipsychotics improve cognitive function, including working memory, in schizophrenia. Some atypical antipsychotics have been reported to activate the locus coeruleus and induce beta-adrenoceptor antagonist sensitive c-Fos-like immunoreactivity in the prefrontal cortex. The present study investigated the effects of chronic treatment of rats with risperidone (1 mg kg(-1) day(-1) s.c.), clozapine (10 mg kg(-1) day(-1) s.c.), or acidified saline vehicle control for 2, 4, or 8 weeks on spatial working memory performance in a delayed matching-to-place water maze task with a 60-s inter-trial retention interval with and without acute challenge with propranolol (10 mg/kg i.p.). Treatment with risperidone for 8 weeks, but not 2 or 4 weeks, significantly improved working memory performance. In contrast, treatment with clozapine for up to 8 weeks did not improve working memory. Acute challenge with propranolol blocked the improvement in working memory produced by chronic treatment with risperidone, but had no significant effect on performance in saline- or clozapine-treated animals. The delayed matching-to-place water maze task may prove valuable in the investigation of the behavioural pharmacology of the cognitive effects of antipsychotic drugs. These data suggest that beta adrenoceptors may contribute to the cognitive effects of chronic treatment with atypical antipsychotics.

A quantitative approach to recording peristaltic activity from segments of rat small intestine in vivo

We have developed methods that allow correlation of propulsive reflexes of the intestine with measurements of intraluminal pressure, fluid movement and spatio-temporal maps of intestinal wall movements for the first time in vivo. A segment of jejunum was cannulated and set up in a Trendelenburg recording system while remaining connected to the vascular and nerve supply of the anaesthetized rat. The resting intraluminal pressure in intact intestine was 2-4 mmHg. Hydrostatic pressures of 2, 4, 8 and 16 mmHg were imposed. At a baseline pressure of 4 mmHg, propulsive waves generated pressures of 9 +/- 1 mmHg, that progressed oral to anal at 2-5 mm s(-1). Individual propulsive waves propelled 0.8 +/- 0.4 mL of fluid. The frequency of propulsive waves increased with pressure, but peristaltic efficiency (mL per contraction) decreased with pressure increase between 4 and 16 mmHg. Atropine, as a bolus, transiently blocked peristalsis, but caused maintained block when infused. Hexamethonium blocked propulsive contractions. Inhibition of nitrergic transmission converted regular peristalsis to non-propulsive contractions. These studies demonstrate the utility of an adapted Trendelenburg method for quantitative investigation of motility and pharmacology of enteric reflexes in vivo.

Investigation of CGRP receptors and peptide pharmacology in human coronary arteries. Characterization with a nonpeptide antagonist.

Calcitonin gene-related peptide (CGRP), adrenomedullin (AM), and amylin are structurally related peptides mediating vasorelaxation in the coronary circulation possibly via CGRP receptors (subtypes 1 or 2). Functional CGRP1 receptors appear to consist of at least three different kinds of proteins: the calcitonin receptor-like receptor (CRLR), receptor-activity-modifying proteins (RAMPs) and the receptor component protein (RCP). No CGRP2 receptor has yet been cloned. Using reverse transcriptase - polymerase chain reaction, the presence of mRNA sequences encoding CRLR, RCP and RAMPs was demonstrated in human coronary arteries. Relaxant responses were studied on isolated segments of coronary arteries after precontraction with U46619 (9,11-dideoxy-11alpha,9alpha-epoxymethano-prostaglandin F(2alpha)). The human peptides alphaCGRP, AM, and amylin induced relaxation with mean pEC50 values of 8.6, 6.8, and 6.3 M, respectively. Preincubation with alphaCGRP(8-37) (10(-7) -10(-5) M) and a novel nonpeptide CGRP antagonist "Compound 1" (WO98/11128) (10(-7)-10(-5) M) caused a dose-dependent rightward shift of the concentration-response curves for alphaCGRP with pA(2) values of 7.0 and 7.1, respectively. Preincubation with alphaCGRP(8-37) (10(-6) M) and Compound 1 (10(-6) M) caused significant rightward shift of the concentration-response curves for AM and amylin as well with pK B values between 6.6 and 7.5. Preincubation with AM(22-52) had no antagonistic effect on the AM and amylin response, neither did diacetoamidomethyl cysteine CGRP cause any concentration dependent (10(-11)-10(-6) M) dilatation. In conclusion, mRNA for the components forming CGRP1 and AM receptors was detected in the human left anterior descending coronary arteries. alphaCGRP, AM, and amylin mediated vasorelaxation via the CGRP1 receptor. Compound 1 acted as a nonpeptide antagonist at the CGRP1 receptor and could thus become a tool for the study of CGRP-mediated functional responses in human tissue.

Clinical pharmacology of higher dose eptifibatide in percutaneous coronary intervention (the PRIDE study)

This study describes the dose-exploration phase of the PRIDE trial, an investigation of the clinical pharmacology of higher dose eptifibatide in patients who underwent elective percutaneous coronary intervention (PCI). Outcomes of treatment with the platelet glycoprotein IIb/IIIa inhibitors were dependent upon proper dosing selection. In this multicenter, placebo-controlled clinical study, 127 patients were randomized 1:1:2:2 into 1 of the following treatment groups: placebo; eptifibatide as a 135 μg/kg bolus followed by a 0.75 μg/kg/min infusion; eptifibatide as a 180 μg/kg bolus with a 2.0 μg/kg/min infusion; or eptifibatide as a 250 μg/kg bolus with a 3.0 μg/kg/min infusion. Light transmission aggregometry was used to determine platelet aggregation in response to 20 μM adenosine diphosphate, and platelet receptor occupancy was also determined. Eptifibatide exhibited linear pharmacokinetics over the dose range studied. Inhibition of platelet aggregation was greater in samples collected in sodium citrate compared with those collected in d-phenylalanyl- l-prolyl- l-arginine chloromethyl ketone. The 180/2.0 dosing regimen achieved 90% inhibition of platelet aggregation immediately (5 minutes) and at steady state (8 to 24 hours). At 1 hour, mean inhibition of platelet aggregation was 80%. Eptifibatide exhibited dose-dependent pharmacodynamics that were dependent upon choice of anticoagulant. A 180 μg/kg bolus followed by a 2.0 μg/kg/min infusion at steady state achieved >80% inhibition of platelet aggregation. With the single-bolus regimen, however, there was an early loss of the inhibition of platelet aggregation before steady state was reached. Additional dose-exploration studies may further optimize eptifibatide dosing.