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1.
Exp Parasitol ; 209: 107823, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31862270

RESUMEN

Typically, antimicrobial peptides (AMPs) are short positive charged peptides serving a key role in innate immunity as well as antimicrobial activity. Discovering novel therapeutic agents is considered as an undeniable demand due to increasing microbial species with antibiotic resistance. In this direction, the unique ability of AMPs to modulate immune responses highlighted them as novel drug candidates in the field of microbiology. Patients affected by leishmaniasis; a neglected tropical disease, confront serious problems for their treatment including resistance to common drugs as well as toxicity and high cost of therapy. So, there is a need for development of new drug candidates to control the diseases. Jellein, a peptide derived from royal jelly of honeybee has been shown to have promising effect against several bacterial and fungal species. In current study, anti-leishmanial effect of Jellein and its lauric acid conjugated form was investigated against two forms of Leishmania major (L. major) parasite. Moreover, cytotoxic effect of these peptides was studied in THP1 cell line and human Red Blood Cells (RBCs). Furthermore, the mechanism of action of peptides on L. major promastigotes was assessed through different methods. The results demonstrated that, conjugation of lauric acid to Jellein not only had no effect on the elevation of antimicrobial activity but also halted it completely. Moreover, Jellein caused a limitation in the number of L. major promastigotes by pore formation as well as changing the membrane potential rather than induction of apoptosis or activation of caspases.


Asunto(s)
Péptidos Catiónicos Antimicrobianos/farmacología , Antiprotozoarios/farmacología , Leishmania major/efectos de los fármacos , Leishmaniasis Cutánea/tratamiento farmacológico , Oligopéptidos/química , Antígenos de Diferenciación de Linfocitos B/farmacología , Péptidos Catiónicos Antimicrobianos/uso terapéutico , Péptidos Catiónicos Antimicrobianos/toxicidad , Antiprotozoarios/uso terapéutico , Antiprotozoarios/toxicidad , Caspasas/efectos de los fármacos , Caspasas/metabolismo , Línea Celular Tumoral , Permeabilidad de la Membrana Celular/efectos de los fármacos , Eritrocitos/efectos de los fármacos , Escherichia coli/efectos de los fármacos , Ácidos Grasos/química , Citometría de Flujo , Hemólisis , Antígenos de Histocompatibilidad Clase II/farmacología , Humanos , Ácidos Láuricos/farmacología , Ácidos Láuricos/uso terapéutico , Ácidos Láuricos/toxicidad , Leishmania major/ultraestructura , Potenciales de la Membrana/efectos de los fármacos , Microscopía Electrónica de Rastreo , Enfermedades Desatendidas/tratamiento farmacológico , Enfermedades Desatendidas/parasitología , Oligopéptidos/farmacología , Oligopéptidos/uso terapéutico , Oligopéptidos/toxicidad
2.
Hypertension ; 74(5): 1200-1214, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31542964

RESUMEN

Endothelial cells line all blood vessels and are critical regulators of vascular tone. In hypertension, disruption of endothelial function alters the release of endothelial-derived vasoactive factors and results in increased vascular tone. Although the release of endothelial-derived vasodilators occurs in a Ca2+-dependent manner, little is known on how Ca2+ signaling is altered in hypertension. A key element to endothelial control of vascular tone is Ca2+ signals at specialized regions (myoendothelial projections) that connect endothelial cells and smooth muscle cells. This work describes disruption in the operation of this key Ca2+ signaling pathway in hypertension. We show that vascular reactivity to phenylephrine is increased in hypertensive (spontaneously hypertensive rat) when compared with normotensive (Wistar Kyoto) rats. Basal endothelial Ca2+ activity limits vascular contraction, but that Ca2+-dependent control is impaired in hypertension. When changes in endothelial Ca2+ levels are buffered, vascular contraction to phenylephrine increased, resulting in similar responses in normotension and hypertension. Local endothelial IP3(inositol trisphosphate)-mediated Ca2+ signals are smaller in amplitude, shorter in duration, occur less frequently, and arise from fewer sites in hypertension. Spatial control of endothelial Ca2+ signaling is also disrupted in hypertension: local Ca2+ signals occur further from myoendothelial projections in hypertension. The results demonstrate that the organization of local Ca2+ signaling circuits occurring at myoendothelial projections is disrupted in hypertension, giving rise to increased contractile responses.


Asunto(s)
Señalización del Calcio/efectos de los fármacos , Endotelio Vascular/metabolismo , Hipertensión/fisiopatología , Fenilefrina/farmacología , Receptores Sensibles al Calcio/metabolismo , Animales , Señalización del Calcio/fisiología , Modelos Animales de Enfermedad , Células Endoteliales/citología , Células Endoteliales/metabolismo , Endotelio Vascular/fisiopatología , Hipertensión/metabolismo , Masculino , Potenciales de la Membrana/efectos de los fármacos , Músculo Liso Vascular/metabolismo , Distribución Aleatoria , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Valores de Referencia , Sensibilidad y Especificidad , Vasoconstricción/efectos de los fármacos , Vasoconstricción/fisiología
3.
Chemistry ; 25(66): 15198-15204, 2019 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-31549755

RESUMEN

Polytheonamide B (1) is a linear 48-mer natural peptide with alternating d- and l-amino acid residues. Compound 1 forms conducting channels for monovalent ions and exhibits potent cytotoxicity against MCF-7 cells. Previously, we reported that nanomolar concentrations of 1 induce plasma membrane depolarization and lysosomal pH disruption, which triggers apoptosis. Here, we report the cellular localization and biological action of a simplified synthetic analogue of 1, polytheonamide mimic 3. Compared with 1, the toxicity of 3 against MCF-7 cells is 16 times weaker. Although its plasma membrane depolarization effect is only 3.6 times lower, more 3 (20-fold) is required to neutralize lysosomal pH. Thus, the effective concentrations for lysosomal neutralization and cytotoxicity by 3 are comparable. These results strongly suggest that the activity of 3 against the lysosomal membrane is more important for apoptotic cell death than its effects on the plasma membrane, and provide valuable information regarding the unique behavior of polytheonamide-based molecules.


Asunto(s)
Membrana Celular/metabolismo , Péptidos y Proteínas de Señalización Intracelular/química , Lisosomas/metabolismo , Apoptosis/efectos de los fármacos , Colorantes Fluorescentes/química , Humanos , Concentración de Iones de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Péptidos y Proteínas de Señalización Intracelular/farmacología , Células MCF-7 , Potenciales de la Membrana/efectos de los fármacos , Espectrometría de Fluorescencia
4.
Molecules ; 24(18)2019 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-31489899

RESUMEN

3-Carene is an antimicrobial monoterpene that occurs naturally in a variety of plants and has an ambiguous antibacterial mechanism against food-borne germs. The antibacterial effects and action mechanism of 3-carene against Gram-positive Brochothrix thermosphacta ACCC 03870 and Gram-negative Pseudomonas fluorescens ATCC 13525 were studied. Scanning electron microscopy (SEM) examination and leakage of alkaline phosphatase (AKP) verified that 3-carene caused more obvious damage to the morphology and wall structure of B. thermosphacta than P. fluorescens. The release of potassium ions and proteins, the reduction in membrane potential (MP), and fluorescein diacetate (FDA) staining further confirmed that the loss of the barrier function of the cell membrane and the leakage of cytoplasmic contents were due to the 3-carene treatment. Furthermore, the disorder of succinate dehydrogenase (SDH), malate dehydrogenase (MDH), pyruvate kinase (PK), and ATP content indicated that 3-carene could lead to metabolic dysfunction and inhibit energy synthesis. In addition, the results from the fluorescence analysis revealed that 3-carene could probably bind to bacterial DNA and affect the conformation and structure of genomic DNA. These results revealed that 3-carene had strong antibacterial activity against B. thermosphacta and P. fluorescens via membrane damage, bacterial metabolic perturbations, and genomic DNA structure disruption, interfering in cellular functions and even causing cell death.


Asunto(s)
Antibacterianos/farmacología , Brochothrix/efectos de los fármacos , Pseudomonas fluorescens/efectos de los fármacos , Brochothrix/genética , Pared Celular/efectos de los fármacos , ADN Bacteriano/química , ADN Bacteriano/efectos de los fármacos , Microbiología de Alimentos , Potenciales de la Membrana/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica de Rastreo , Pseudomonas fluorescens/genética
5.
Biophys Chem ; 254: 106247, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31472460

RESUMEN

The ß-cells dynamics is the regulator of insulin secretion in the pancreas, and its investigation is a central aspect in designing effective treatment strategies for diabetes. Despite great efforts, much is still unknown about the complex organization of such endocrine cells and realistic mathematical modeling represents a useful tool to elucidate key aspects of glucose control in humans. In this contribution, we study the human ß-cells collective behaviour, by modeling their electric and metabolic coupling in a cluster, of size and architecture similar to human islets of Langerhans. We focus on the effect of coupling on various dynamics regimes observed in the islets, that are spiking and bursting on multiple timescales. In particular, we test the effect of hubs, that are highly glucose-sensitive ß-cells, on the overall network dynamics, observing different modulation depending on the timescale of the dynamics. By properly taking into account the role of cells heterogeneity, recently emerged, our model effectively describes the effect of hubs on the synchronization of the islet response and the correlation of ß-cells activity.


Asunto(s)
Células Secretoras de Insulina/fisiología , Modelos Biológicos , Glucosa/farmacología , Humanos , Insulina/metabolismo , Células Secretoras de Insulina/citología , Potenciales de la Membrana/efectos de los fármacos
6.
Plant Physiol Biochem ; 142: 528-535, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31473567

RESUMEN

Tryptophan at concentrations higher than 0.1 mM, triggered characteristic early physiological effects such as rapid (within 5 min) dose-dependent membrane hyperpolarization in Mimosa pudica motor cells and modification of the time course of the spontaneous proton efflux monitored in the incubation medium of pulvinar tissues. The rapid modifications of the leaf turgor-mediated movements seen on the primary pulvini of M. pudica following a shock and on Cassia fasciculata leaflets during a transition from light to darkness indicate that tryptophan disturbed the ionic migrations involved in the electrophysiological events and in the osmocontractile reaction of the motor cells. These reactions were specific to tryptophan compared to those induced by serine and 5-hydroxytryptophan. The tryptophan mode of action cannot be linked to a direct modification of the plasma membrane H+-ATPase activity as monitored on purified pulvinar plasma membrane vesicles. The tryptophan metabolism-linked products tryptamine and indole also inhibited the motile reactions, activated in a continuous manner the H+ secretion of pulvinar tissues and showed properties of a protonophore and an ATPase activity inhibitor on plasma membrane vesicles, respectively. The specific behavior of tryptophan in the reaction studies here is discussed in light of the previously reported action of phytohormones.


Asunto(s)
Cassia/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Mimosa/efectos de los fármacos , Triptófano/farmacología , Cassia/citología , Cassia/fisiología , Membrana Celular/metabolismo , Relación Dosis-Respuesta a Droga , Potenciales de la Membrana/efectos de los fármacos , Mimosa/citología , Mimosa/fisiología , Movimiento/efectos de los fármacos , Movimiento/fisiología , Hojas de la Planta/citología , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/fisiología , Triptófano/metabolismo
7.
Int J Nanomedicine ; 14: 5595-5609, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31413565

RESUMEN

Background: Platinum nanoparticles (PtNPs) have been considered a nontoxic nanomaterial and been clinically used in cancer chemotherapy. PtNPs can also be vehicle exhausts and environmental pollutants. These situations increase the possibility of human exposure to PtNPs. However, the potential biotoxicities of PtNPs including that on cardiac electrophysiology have been poorly understood. Methods: Ion channel currents of cardiomyocytes were recorded by patch clamp. Heart rhythm was monitored by electrocardiogram recording. Morphology and characteristics of PtNPs were examined by transmission electron microscopy, dynamic light scattering and electrophoretic light scattering analyses. Results: In cultured neonatal mice ventricular cardiomyocytes, PtNPs with diameters 5 nm (PtNP-5) and 70 nm (PtNP-70) concentration-dependently (10-9 - 10-5 g/mL) depolarized the resting potentials, suppressed the depolarization of action potentials and delayed the repolarization of action potentials. At the ion channel level, PtNPs decreased the current densities of INa, IK1 and Ito channels, but did not affect the channel activity kinetics. In vivo, PtNP-5 and PtNP-70 dose-dependently (3-10 mg/kg, i.v.) decreased the heart rate and induced complete atrioventricular conduction block (AVB) at higher doses. Both PtNP-5 and PtNP-70 (10-9 - 10-5 g/mL) did not significantly increase the generation of ROS and leak of lactate dehydrogenase (LDH) from cardiomyocytes within 5 mins after exposure except that only very high PtNP-5 (10-5 g/mL) slightly increased LDH leak. The internalization of PtNP-5 and PtNP-70 did not occur within 5 mins but occurred 1 hr after exposure. Conclusion: PtNP-5 and PtNP-70 have similar acute toxic effects on cardiac electrophysiology and can induce threatening cardiac conduction block. These acute electrophysiological toxicities of PtNPs are most likely caused by a nanoscale interference of PtNPs on ion channels at the extracellular side, rather than by oxidative damage or other slower biological processes.


Asunto(s)
Frecuencia Cardíaca/efectos de los fármacos , Canales Iónicos/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Nanopartículas del Metal/toxicidad , Miocitos Cardíacos/metabolismo , Platino (Metal)/toxicidad , Pruebas de Toxicidad Aguda , Animales , Animales Recién Nacidos , Células Cultivadas , Electrocardiografía , Endocitosis/efectos de los fármacos , Sistema de Conducción Cardíaco/efectos de los fármacos , Ventrículos Cardíacos/citología , Activación del Canal Iónico/efectos de los fármacos , Cinética , Nanopartículas del Metal/administración & dosificación , Nanopartículas del Metal/ultraestructura , Ratones Endogámicos C57BL , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/ultraestructura , Estrés Oxidativo/efectos de los fármacos , Platino (Metal)/administración & dosificación
8.
Int J Mol Sci ; 20(15)2019 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-31370156

RESUMEN

Diabetes mellitus is one of the major risk factors for cardiovascular disease and is an important health issue worldwide. Long-term diabetes causes endothelial dysfunction, which in turn leads to diabetic vascular complications. Endothelium-derived nitric oxide is a major vasodilator in large-size vessels, and the hyperpolarization of vascular smooth muscle cells mediated by the endothelium plays a central role in agonist-mediated and flow-mediated vasodilation in resistance-size vessels. Although the mechanisms underlying diabetic vascular complications are multifactorial and complex, impairment of endothelium-dependent hyperpolarization (EDH) of vascular smooth muscle cells would contribute at least partly to the initiation and progression of microvascular complications of diabetes. In this review, we present the current knowledge about the pathophysiology and underlying mechanisms of impaired EDH in diabetes in animals and humans. We also discuss potential therapeutic approaches aimed at the prevention and restoration of EDH in diabetes.


Asunto(s)
Factores Biológicos/genética , Enfermedades Cardiovasculares/metabolismo , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Endotelio Vascular/metabolismo , Miocitos del Músculo Liso/metabolismo , Canales de Potasio Calcio-Activados/genética , Animales , Factores Biológicos/metabolismo , Enfermedades Cardiovasculares/tratamiento farmacológico , Enfermedades Cardiovasculares/etiología , Enfermedades Cardiovasculares/genética , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/genética , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/patología , Uniones Comunicantes/efectos de los fármacos , Uniones Comunicantes/metabolismo , Uniones Comunicantes/patología , Regulación de la Expresión Génica , Humanos , Hipoglucemiantes/uso terapéutico , Resistencia a la Insulina , Potenciales de la Membrana/efectos de los fármacos , Miocitos del Músculo Liso/efectos de los fármacos , Miocitos del Músculo Liso/patología , Canales de Potasio Calcio-Activados/metabolismo , Factores de Riesgo , Transducción de Señal , Vasodilatación/efectos de los fármacos
9.
PLoS Comput Biol ; 15(8): e1006938, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31469828

RESUMEN

The mechanism(s) of action of most commonly used pharmacological blockers of voltage-gated ion channels are well understood; however, this knowledge is rarely considered when interpreting experimental data. Effects of blockade are often assumed to be equivalent, regardless of the mechanism of the blocker involved. Using computer simulations, we demonstrate that this assumption may not always be correct. We simulate the blockade of a persistent sodium current (INaP), proposed to underlie rhythm generation in pre-Bötzinger complex (pre-BötC) respiratory neurons, via two distinct pharmacological mechanisms: (1) pore obstruction mediated by tetrodotoxin and (2) altered inactivation dynamics mediated by riluzole. The reported effects of experimental application of tetrodotoxin and riluzole in respiratory circuits are diverse and seemingly contradictory and have led to considerable debate within the field as to the specific role of INaP in respiratory circuits. The results of our simulations match a wide array of experimental data spanning from the level of isolated pre-BötC neurons to the level of the intact respiratory network and also generate a series of experimentally testable predictions. Specifically, in this study we: (1) provide a mechanistic explanation for seemingly contradictory experimental results from in vitro studies of INaP block, (2) show that the effects of INaP block in in vitro preparations are not necessarily equivalent to those in more intact preparations, (3) demonstrate and explain why riluzole application may fail to effectively block INaP in the intact respiratory network, and (4) derive the prediction that effective block of INaP by low concentration tetrodotoxin will stop respiratory rhythm generation in the intact respiratory network. These simulations support a critical role for INaP in respiratory rhythmogenesis in vivo and illustrate the importance of considering mechanism when interpreting and simulating data relating to pharmacological blockade.


Asunto(s)
Modelos Neurológicos , Sistema Respiratorio/efectos de los fármacos , Sistema Respiratorio/inervación , Bloqueadores de los Canales de Sodio/farmacología , Animales , Biología Computacional , Simulación por Computador , Técnicas In Vitro , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Red Nerviosa/efectos de los fármacos , Red Nerviosa/fisiología , Neuronas/efectos de los fármacos , Neuronas/fisiología , Centro Respiratorio/efectos de los fármacos , Centro Respiratorio/fisiología , Sistema Respiratorio/metabolismo , Riluzol/farmacología , Canales de Sodio/metabolismo , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/fisiología , Tetrodotoxina/farmacología
10.
J Integr Neurosci ; 18(2): 163-172, 2019 06 30.
Artículo en Inglés | MEDLINE | ID: mdl-31321957

RESUMEN

In this paper, the modulation of ascending commissural interneurons by N-methyl-D-aspartate was investigated in neonatal rats by using retrograde labeling and whole-cell patch clamp. Data shows these interneurons can be divided into three types (single spike, phasic, and tonic) based on their firing patterns. A hyperpolarization-activated nonselective cation current and persistent inward current are expressed in these interneurons. The parameters studied (n = 48) include: resting membrane potential (-59.2 ± 0.8 mV), input resistance (964.4 ± 49.3 MΩ), voltage threshold (-39.5 ± 0.6 mV), rheobase (13.5 ± 0.7 pA), action potential height (55.6 ± 2.2 mV), action potential half-width (2.8 ± 0.1 ms), afterhyperpolarization magnitude (16.1 ± 1.2 mV) and half-decay (217.9 ± 10.7 ms). 10 µM N-methyl-D-aspartate increases excitability of ascending commissural interneurons by depolarizing the membrane potential, hyperpolarizing voltage threshold, reducing rheobase, and shifting the frequency-current relationship to the left. N-methyl-Daspartate enhances persistent inward currents but reduces hyperpolarization-activated nonselective cation currents. This research uncovers unique ionic and intrinsic properties of ascending commissural interneurons which can be modulated by major excitatory neurotransmitters such as N-methyl-D-aspartate to potentially facilitate left-right alternation during locomotion.


Asunto(s)
Interneuronas Comisurales/fisiología , Potenciales de la Membrana , N-Metilaspartato/fisiología , Médula Espinal/fisiología , Potenciales de Acción/efectos de los fármacos , Animales , Animales Recién Nacidos , Interneuronas Comisurales/citología , Interneuronas Comisurales/efectos de los fármacos , Agonistas de Aminoácidos Excitadores/administración & dosificación , Potenciales de la Membrana/efectos de los fármacos , N-Metilaspartato/administración & dosificación , Ratas Wistar , Médula Espinal/citología , Médula Espinal/efectos de los fármacos
11.
J Nutr Sci Vitaminol (Tokyo) ; 65(3): 258-263, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31257266

RESUMEN

Allicin, an antioxidant from garlic, is known to regulate intestinal contractions, but its effect on intestinal ion transport is unclear. The aim of this study was to examine the role of allicin in the regulation of electrogenic ion transport in rat intestine by measuring the transmural potential difference (ΔPD). Allicin induced significant positive ΔPD, when administered to the serosal side of the colonic mucosal-submucosal preparation. Allicin-induced colonic ΔPD was largely diminished by incubation in the chloride-free solution, although the transient peak of ΔPD after application of allicin remained. This transient peak of ΔPD was significantly diminished in both the chloride- and the bicarbonate-free incubation solution. Induction of ΔPD by allicin was greatly diminished by AP-18, an inhibitor of the transient receptor potential (TRP) cation channel subfamily A member 1, TRPA1. Both alliin and S-allylcysteine, the analogues of allicin, had no effect on ΔPD and did not affect allicin-induced ΔPD in the colon. These results suggest that allicin mainly evokes the electrogenic chloride secretion and only partially increases the electrogenic bicarbonate secretion via TRPA1.


Asunto(s)
Bicarbonatos/metabolismo , Cloruros/metabolismo , Colon/efectos de los fármacos , Ácidos Sulfínicos/farmacología , Canal Catiónico TRPA1 , Animales , Colon/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Canal Catiónico TRPA1/efectos de los fármacos , Canal Catiónico TRPA1/metabolismo
12.
Eur J Med Chem ; 180: 291-309, 2019 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-31319265

RESUMEN

Activation of the CB2 receptor is an attractive therapeutic strategy for the treatment of a wide range of inflammatory diseases. However, receptor subtype selectivity is necessary in order to circumvent the psychoactive effects associated with activation of the CB1 receptor. We aimed to use potent, non-selective synthetic cannabinoids designer drugs to develop selective CB2 receptor agonists. Simple structural modifications such as moving the amide substituent of 3-amidoalkylindole synthetic cannabinoids to the 2-position and bioisosteric replacement of the indole core to the 7-azaindole scaffold are shown to be effective and general strategies to impart receptor subtype selectivity. 2-Amidoalkylindole 16 (EC50 CB1 > 10 µM, EC50 CB2 = 189 nM) and 3-amidoalkyl-7-azaindole 21 (EC50 CB1 > 10 µM, EC50 = 49 nM) were found to be potent and selective agonists with favourable physicochemical properties. Docking studies were used to elucidate the molecular basis for the observed receptor subtype selectivity for these compounds.


Asunto(s)
Cannabinoides/farmacología , Indoles/farmacología , Receptor Cannabinoide CB2/agonistas , Animales , Cannabinoides/síntesis química , Cannabinoides/química , Línea Celular Tumoral , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Indoles/química , Potenciales de la Membrana/efectos de los fármacos , Ratones , Estructura Molecular , Receptor Cannabinoide CB2/química , Relación Estructura-Actividad
13.
Inorg Chem ; 58(14): 9067-9075, 2019 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-31268715

RESUMEN

The binuclear platinum(II) boron-dipyrromethene (BODIPY) complex [{Pt(dach)}2(µ-Dcrb)] (DP), where dach is 1,2-diaminocyclohexane and H4Dcrb is a morpholine-conjugated BODIPY-linked dicatechol bridging ligand, was prepared for lysosome organelle targeting and near-IR (NIR) light (600-720 nm) induced photocytotoxic activity. The platinum complex [Pt(dach)(cat)] (CP), where H2cat is catechol, was synthesized and used as a control complex without bearing the BODIPY unit. The complex DP displayed a band at 660 nm (ε = 2.1 × 104 M-1 cm-1) in the red region of the UV-visible spectrum recorded in 10% dimethyl sulfoxide/Dulbecco's Modified Eagle's Medium (DMSO/DMEM, pH 7.2). The complex DP and the BODIPY ligand displayed emission in 10% DMSO-DMEM (pH 7.2) giving an λem value of 668 nm (λex = 650 nm) with a ΦF value of 0.02 for DP and 0.16 for H4Dcrb (ΦF, fluorescence quantum yield). Titration experiments using 1,3-diphenylisobenzofuran (DPBF) indicated that the complex DP and H4Dcrb on irradiation with near-IR light of 600-720 nm generated singlet oxygen (1O2) as the ROS (reactive oxygen species). The complex DP showed significant lysosomal localization and remarkable apoptotic photodynamic therapy (PDT) effects, giving half-maximal inhibitory concentration values (IC50) within 0.6-3.4 µM in HeLa cervical cancer, A549 lung cancer, and MDA-MB231 multidrug resistant cancer cells, while being essentially nontoxic in the dark and in the HPL1D immortalized lung epithelial normal cells. The acridine orange assay using A549 cells showed lysosomal membrane permeabilization by the complex DP under near-IR light (600-720 nm). This complex on near-IR light (600-720 nm) activation in A549 cells induced apoptotic cell death, as observed from an Annexin-V FITC assay.


Asunto(s)
Compuestos de Boro/química , Lisosomas/química , Fotoquimioterapia , Compuestos de Platino/química , Pirroles/química , Compuestos de Boro/farmacología , Línea Celular Tumoral , Cristalografía por Rayos X , Humanos , Potenciales de la Membrana/efectos de los fármacos , Estructura Molecular , Compuestos de Platino/farmacología
14.
Mol Pharmacol ; 96(3): 330-344, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31253645

RESUMEN

hERG K+ channel is important for controlling the duration of cardiac action potentials. Amiodarone (AMD), a widely prescribed class III antiarrhythmic, could inhibit hERG currents with relatively few tachyarrhythmic adverse events. We use injected Xenopus oocyte with two-electrode voltage clamp techniques to characterize the action of AMD on hERG channels. We found that AMD binds to the resting hERG channel with an apparent dissociation constant of ∼1.4 µM, and inhibits hERG currents at mild and strong depolarization pulses by slowing activation and enhancing inactivation, respectively, at 22°C. The activation kinetics of hERG channel activation are much faster, but inactivation kinetics are slower at 37°C. AMD accordingly has a 15% to 20% weaker and stronger inhibitory effect at mild and strong depolarization (e.g., -60 and +30 mV, 0.3-second pulse), respectively. In the meanwhile, the resurgent hERG tail currents are dose-dependently inhibited by AMD without altering the kinetics of current decay at both 22°C and 37°C, indicating facilitation of recovery from inactivation via the silent route. Most importantly, AMD no longer inhibits but enhances hERG currents at a mild pulse shortly after a prepulse at 37°C, but not so much at 22°C. We conclude that AMD is an effective hERG channel-gating modifier capable of lengthening the plateau phase of cardiac action potential (without increasing the chance of afterdepolarization). AMD, however, should be used with caution in hypothermia or the other scenarios that slow hERG channel activation. SIGNIFICANCE STATEMENT: It is known that amiodarone (AMD) acts on hERG K+ channels to treat cardiac arrhythmias with relatively little arrhythmogenicity. We found that AMD enhances hERG channel inactivation but slows activation as well as recovery from inactivation, and thus has a differential inhibition and enhancement effect on hERG currents at different phases of membrane voltage changes, especially at 37°C, but not so much at 22°C. AMD is therefore a relatively ideal agent against tachyarrhythmia at 37°C, but should be more cautiously used at lower temperatures or relevant pathophysiological/pharmacological scenarios associated with slower hERG channel activation because of the increased chances of adverse events.


Asunto(s)
Amiodarona/farmacología , Canal de Potasio ERG1/metabolismo , Bloqueadores de los Canales de Potasio/farmacología , Xenopus laevis/genética , Animales , Animales Modificados Genéticamente , Fenómenos Biofísicos , Canal de Potasio ERG1/antagonistas & inhibidores , Canal de Potasio ERG1/genética , Humanos , Potenciales de la Membrana/efectos de los fármacos , Técnicas de Placa-Clamp , Temperatura Ambiental , Xenopus laevis/crecimiento & desarrollo
15.
Environ Int ; 129: 333-342, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31150975

RESUMEN

The dissemination of antibiotic resistance genes (ARGs), especially via the plasmid-mediated conjugation, is becoming a pervasive global health threat. This study reported that this issue can be worse by CO2, as increased CO2 was found to facilitate the conjugative transfer of ARGs carried on plasmid RP4 by 2.4-9.0 and 1.3-3.8 fold within and across genera, respectively. Mechanistic studies revealed that CO2 benefitted the cell-to-cell contact by increasing cell surface hydrophobicity and decreasing cell surface charge, both of which resulted in the reduced intercellular repulsion. Besides, the transcriptional expression of genes responsible for global regulator (korA, korB and trbA), plasmid transfer and replication system (trfAp), and mating pair formation system (traF and traG) were all influenced by CO2, facilitating the mobilization and channel transfer of plasmid. Furthermore, the presence of CO2 induced the release of intracellular Ca2+ and increased the transmembrane potential of recipients, which contributed to the increased proton motive force (PMF), providing more power for DNA uptake. This is the first study addressing the potential risks of increased CO2 on the propagation of ARGs, which provides a new insight into the concerns of anthropogenic CO2 emissions and CO2 storage.


Asunto(s)
Bacterias/efectos de los fármacos , Dióxido de Carbono/farmacología , Conjugación Genética/efectos de los fármacos , Farmacorresistencia Bacteriana/efectos de los fármacos , Contaminantes Ambientales/farmacología , Antibacterianos/farmacología , Escherichia coli/efectos de los fármacos , Genes Bacterianos , Potenciales de la Membrana/efectos de los fármacos , Plásmidos
16.
Biomed Res Int ; 2019: 6261951, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31183371

RESUMEN

Background/Aims: Voltage-dependent potassium channels (Kv1.3) are predominantly expressed in lymphocyte plasma membranes. These channels are critical for the activation and proliferation of lymphocytes. Since second-generation antihistamines are lipophilic and exert immunomodulatory effects, they are thought to affect the lymphocyte Kv1.3-channel currents. Methods: Using the patch-clamp whole-cell recording technique in murine thymocytes, we tested the effects of second-generation antihistamines, such as cetirizine, fexofenadine, azelastine, and terfenadine, on the channel currents and the membrane capacitance. Results: These drugs suppressed the peak and the pulse-end currents of the channels, although the effects of azelastine and terfenadine on the peak currents were more marked than those of cetirizine and fexofenadine. Both azelastine and terfenadine significantly lowered the membrane capacitance. Since these drugs did not affect the process of endocytosis in lymphocytes, they were thought to have interacted directly with the plasma membranes. Conclusions: Our study revealed for the first time that second-generation antihistamines, including cetirizine, fexofenadine, azelastine, and terfenadine, exert suppressive effects on lymphocyte Kv1.3-channels. The efficacy of these drugs may be related to their immunomodulatory mechanisms that reduce the synthesis of inflammatory cytokine.


Asunto(s)
Antagonistas de los Receptores Histamínicos H1/farmacología , Inmunomodulación/efectos de los fármacos , Canal de Potasio Kv1.3/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Timocitos/metabolismo , Animales , Masculino , Ratones , Técnicas de Placa-Clamp
17.
Mol Cells ; 42(6): 470-479, 2019 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-31250620

RESUMEN

Interstitial cells of Cajal (ICCs) are pacemaker cells that exhibit periodic spontaneous depolarization in the gastrointestinal (GI) tract and generate pacemaker potentials. In this study, we investigated the effects of ghrelin and motilin on the pacemaker potentials of ICCs isolated from the mouse small intestine. Using the whole-cell patch-clamp configuration, we demonstrated that ghrelin depolarized pacemaker potentials of cultured ICCs in a dose-dependent manner. The ghrelin receptor antagonist [D-Lys] GHRP-6 completely inhibited this ghrelin-induced depolarization. Intracellular guanosine 5'-diphosphate-ß-S and pre-treatment with Ca2+free solution or thapsigargin also blocked the ghrelin-induced depolarization. To investigate the involvement of inositol triphosphate (IP3), Rho kinase, and protein kinase C (PKC) in ghrelin-mediated pacemaker potential depolarization of ICCs, we used the IP3 receptor inhibitors 2-aminoethoxydiphenyl borate and xestospongin C, the Rho kinase inhibitor Y-27632, and the PKC inhibitors staurosporine, Go6976, and rottlerin. All inhibitors except rottlerin blocked the ghrelin-induced pacemaker potential depolarization of ICCs. In addition, motilin depolarized the pacemaker potentials of ICCs in a similar dose-dependent manner as ghrelin, and this was also completely inhibited by [D-Lys] GHRP-6. These results suggest that ghrelin induced the pacemaker potential depolarization through the ghrelin receptor in a G protein-, IP3-, Rho kinase-, and PKC-dependent manner via intracellular and extracellular Ca2+ regulation. In addition, motilin was able to depolarize the pacemaker potentials of ICCs through the ghrelin receptor. Therefore, ghrelin and its receptor may modulate GI motility by acting on ICCs in the murine small intestine.


Asunto(s)
Ghrelina/farmacología , Células Intersticiales de Cajal/efectos de los fármacos , Potenciales de la Membrana/efectos de los fármacos , Motilina/farmacología , Acetofenonas/farmacología , Amidas/farmacología , Animales , Benzopiranos/farmacología , Compuestos de Boro/metabolismo , Calcio/metabolismo , Carbazoles/farmacología , Motilidad Gastrointestinal/fisiología , Receptores de Inositol 1,4,5-Trifosfato/antagonistas & inhibidores , Células Intersticiales de Cajal/fisiología , Intestino Delgado/fisiología , Compuestos Macrocíclicos/farmacología , Ratones , Ratones Endogámicos ICR , Oligopéptidos/metabolismo , Oxazoles/farmacología , Proteína Quinasa C/antagonistas & inhibidores , Proteína Quinasa C/metabolismo , Piridinas/farmacología , Receptores de Ghrelina/antagonistas & inhibidores , Receptores de Ghrelina/metabolismo , Transducción de Señal , Estaurosporina/farmacología , Tapsigargina/farmacología , Quinasas Asociadas a rho/antagonistas & inhibidores , Quinasas Asociadas a rho/metabolismo
18.
Eur J Pharmacol ; 855: 50-55, 2019 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-31063774

RESUMEN

Previous studies indicated that one of the action targets of carvedilol is the voltage-gated potassium (Kv) channel, which has a fundamental role in the control of electrical properties in excitable cells. It is not clear whether this compound exerts any actions specifically on delayed rectifier Kv2.1 channels. The present study is conducted on Kv2.1 currents heterologously expressed in HEK293 cells to characterize the block by carvedilol in detail, identifying molecular determinants and providing biophysical insights of the block. Macroscopic Kv2.1 currents obtained by whole-cell recording were substantially inhibited after addition of carvedilol with an IC50 value of 5.1 µM. This drug also led to a largely hyperpolarizing shift (30 mV) of the inactivation curve, which may contribute to the blocking action due to more inactivation of Kv2.1 currents occurred in depolarization potentials. Mutations at Y380 (a putative TEA binding site) and K356 (a K+ binding site) in the outer vestibule of Kv2.1 channels significantly eliminated the inhibitory effects of carvedilol and prevented the leftward shift of inactivation. Moreover, mutations at above positions modulated the effects of carvedilol on the deactivation but not activation kinetics of Kv2.1 channels. Collected data indicate that carvedilol can exert a blocking effect on the closed-state of Kv2.1 channels, and specific residues within the S5-P and P-S6 linkers in the outer vestibule may play crucial roles in carvedilol-induced blocking for Kv2.1 channels.


Asunto(s)
Carvedilol/farmacología , Bloqueadores de los Canales de Potasio/farmacología , Canales de Potasio Shab/antagonistas & inhibidores , Células HEK293 , Humanos , Activación del Canal Iónico/efectos de los fármacos , Potenciales de la Membrana/efectos de los fármacos , Canales de Potasio Shab/metabolismo
19.
Eur J Pharmacol ; 855: 160-166, 2019 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-31063775

RESUMEN

P2Y1 receptors play an essential role in inhibitory neuromuscular transmission in the gastrointestinal tract. The signalling pathway involves the opening of small conductance calcium activated potassium-channels (Kca2 family) that results in smooth muscle hyperpolarization and relaxation. Inorganic polyphosphates and dinucleotidic polyphosphates are putative neurotransmitters that potentially act on P2Y1 receptors. A pharmacological approach using both orthosteric (MRS2500) and allosteric (BPTU) blockers of the P2Y1 receptor and openers (CyPPA) and blockers (apamin) of Kca2 channels was used to pharmacologically characterise the effect of these neurotransmitters. Organ bath and microelectrodes were used to evaluate the effect of P1,P4-Di (adenosine-5') tetraphosphate ammonium salt (Ap4A), inorganic polyphosphates (PolyP) and CyPPA on spontaneous contractions and membrane potential of mouse colonic smooth muscle cells. PolyP neither modified contractions nor membrane potential. In contrast, Ap4A caused a concentration-dependent inhibition of spontaneous contractions reaching a maximum effect at 100 µM Ap4A response was antagonised by MRS2500 (1 µM), BPTU (3 µM) and apamin (1 µM). CyPPA (10 µM) inhibited spontaneous contractions and this response was antagonised by apamin but it was not affected by MRS2500 or BPTU. Both CyPPA and Ap4A caused smooth muscle hyperpolarization that was blocked by apamin and MRS2500 respectively. We conclude that Ap4A but not PolyP activates P2Y1 receptors causing smooth muscle hyperpolarization and relaxation. Ap4A signalling causes activation of Kca2 channels through activation of P2Y1 receptors. In contrast, CyPPA acts directly on Kca2 channels. Further studies are needed to evaluate if dinucleotidic polyphosphates are released from inhibitory motor neurons.


Asunto(s)
Colon/efectos de los fármacos , Fosfatos de Dinucleósidos/farmacología , Relajación Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Receptores Purinérgicos P2Y1/metabolismo , Regulación Alostérica/efectos de los fármacos , Animales , Colon/fisiología , Nucleótidos de Desoxiadenina/farmacología , Femenino , Activación del Canal Iónico/efectos de los fármacos , Potenciales de la Membrana/efectos de los fármacos , Ratones , Músculo Liso/citología , Músculo Liso/metabolismo , Bloqueadores de los Canales de Potasio/farmacología , Antagonistas del Receptor Purinérgico P2Y/farmacología , Transducción de Señal/efectos de los fármacos , Canales de Potasio de Pequeña Conductancia Activados por el Calcio/metabolismo
20.
Neuroscience ; 410: 108-117, 2019 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-31085281

RESUMEN

Opioid prescription and illegal use have been soaring, and it has become a global concern. Adolescence, as a critical developmental period, is radically influenced by drug exposure. In the recent decade, transgenerational effects of paternal environmental exposure have been given greater consideration. There is compelling evidence for the effect of paternal drug abuse such as alcohol, cocaine, and nicotine on the offspring; however, a limited number of studies have focused on the paternal effect of opioids during adolescence on progeny. Locus coeruleus (LC) is a noradrenergic nucleus involved in different brain functions and cognitive processes. The present study aimed to investigate the transgenerational effect of adolescent morphine exposure on electrophysiological properties of LC neurons of the offspring. For this purpose, adolescent male rats received morphine or saline for 10 days between postnatal days 31 and 40, and then after 20 days of washout period, they were mated with naïve female rats. Whole cell patch clamp recordings were performed in current clamp configuration from LC neurons of 14-21-day-old male offspring. The results demonstrated that the decay slope of the action potentials and the amplitude of afterhyperpolarization potential increased in morphine sired animals. Moreover, the duration of action potentials decreased in morphine sired animals. Besides, the coefficient of variation of interspike intervals increased in morphine sired animals compared to the saline sired ones. Overall, the altered electrophysiological properties observed in this study may suggest a functional enhancement of Ca2+ activated K+ channels in LC neurons of morphine sired animals.


Asunto(s)
Analgésicos Opioides/toxicidad , Locus Coeruleus/efectos de los fármacos , Morfina/toxicidad , Neuronas/efectos de los fármacos , Exposición Paterna/efectos adversos , Factores de Edad , Animales , Femenino , Locus Coeruleus/fisiología , Masculino , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Neuronas/fisiología , Técnicas de Cultivo de Órganos , Embarazo , Ratas , Ratas Wistar
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