Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 460
Filtrar
1.
Medicine (Baltimore) ; 99(28): e21117, 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32664137

RESUMO

INTRODUCTION: we report on the first case of a woman affected by chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and recessive myotonia congenita (MC), treated with mexiletine. We aimed at describing the possible role of mexiletine in CIDP management. PATIENT CONCERNS: A 44-year-old female affected by CIDP and MC, gained beneficial effects for CIDP symptoms (muscle weakness, cramps, and fatigue) and relapses, after mexiletine intake (200 mg twice a day). The patient presented with detrimental effects after mexiletine drop out, with a worsening of CIDP symptoms. INTERVENTIONS: The patient reported a nearly complete remission of muscle stiffness and weakness up to 3 years since mexiletine intake. Then, she developed an allergic reaction with glottis edema, maybe related to mexiletine intake, as per emergency room doctors' evaluation, who suggested withdrawing the drug. OUTCOMES: The patient significantly worsened after the medication drop out concerning both CIDP and MC symptoms. CONCLUSION: This is the first report on the association of CIDP and MC in the same patient. Such diseases may share some clinical symptoms related to a persistent sodium currents increase, which maybe due either to the over-expression of sodium channels following axonal damage due to demyelination or to the chloride channel genes mutations. This is the possible reason why mexiletine maybe promising to treat CIDP symptoms.


Assuntos
Mexiletina/uso terapêutico , Miotonia Congênita/complicações , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/tratamento farmacológico , Adulto , Doença Crônica , Feminino , Seguimentos , Humanos , Miotonia Congênita/diagnóstico , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/complicações , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/diagnóstico , Recidiva , Bloqueadores do Canal de Sódio Disparado por Voltagem/uso terapêutico , Suspensão de Tratamento
2.
Expert Opin Drug Saf ; 19(2): 131-138, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31914330

RESUMO

Introduction: Lacosamide has been used in epilepsy patients in the United States, Europe and Asia since it was approved by the FDA in 2008. Many patients have benefited from this drug as a new generation of sodium channel blocker. With the worldwide use of this drug, its adverse effects have gradually emerged, especially some rare adverse events.Areas covered: The present review aims to summarize the adverse effects of lacosamide reported in the literature in recent years to promote the safe clinical application of the drug.Expert opinion: In more than 10 years of experience in drug usage, adverse reactions of lacosamide have also been gradually discovered. The review showed that lacosamide is safe and effective in antiepileptic treatment, and its common side effects are dizziness, headache, drowsiness, diplopia, and cardiovascular abnormalities. Skin rashes, hematotoxicity and heart damage, psychological symptoms and suicide risk have also been reported and emphasized.


Assuntos
Anticonvulsivantes/efeitos adversos , Epilepsia/tratamento farmacológico , Lacosamida/efeitos adversos , Animais , Anticonvulsivantes/administração & dosagem , Humanos , Lacosamida/administração & dosagem , Bloqueadores do Canal de Sódio Disparado por Voltagem/administração & dosagem , Bloqueadores do Canal de Sódio Disparado por Voltagem/efeitos adversos
3.
Chem Biol Interact ; 315: 108890, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31678597

RESUMO

The monoterpenoid terpinen-4-ol (4TERP) is known to inhibit cell excitability, has low toxicity and important pharmacological activities, which are likely related to neural excitability, such as anti-inflammatory, antiepileptic and antinociceptive effects. However, the pharmacological characteristics and mechanisms underlying the effects of 4TERP on blockade of neural action potential are not completely elucidated. Since Na+ current (INa) through voltage-dependent Na+ channels (NaV) is a major mechanism for excitability, the present study investigated the pharmacological characteristics and mechanisms of the action of 4TERP on INa through NaV. For this aim, dissociated small neurons of dorsal root ganglia of adult rats were used for whole cell patch-clamp recordings. 4TERP concentration-dependently inhibits INa (IC50 0.8 ±â€¯0.3 mM; pharmacological efficacy 42.89 ±â€¯5.54%). 4TERP interfered with INa through a mechanism with various components, which includes predominantly channel pore block and sensitivity to frequency of use. In presence of 4TERP (3 mM), decreasing stimulation from 5 Hz to very low frequency (75 s of quiescence previously to stimulation) induced INa decrease to 65.17 ±â€¯5.86% of control. 4TERP also altered (left shift) voltage sensitivity of the steady state activation of NaV. Data are discussed aiming to interpret the importance of blockade of INa through NaV as participant of 4TERP-induced inhibition of membrane excitability.


Assuntos
Gânglios Espinais/efeitos dos fármacos , Monoterpenos/farmacologia , Neurônios/efeitos dos fármacos , Terpenos/farmacologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Canais de Sódio Disparados por Voltagem/metabolismo , Potenciais de Ação/efeitos dos fármacos , Animais , Feminino , Gânglios Espinais/metabolismo , Masculino , Neurônios/metabolismo , Técnicas de Patch-Clamp/métodos , Ratos , Ratos Wistar
4.
Mar Drugs ; 17(12)2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31817438

RESUMO

Severe arrhythmias-such as ventricular arrhythmias-can be fatal, but treatment options are limited. The effects of a combined formulation of tetrodotoxin (TTX) and lidocaine (LID) on severe arrhythmias were studied. Patch clamp recording data showed that the combination of LID and TTX had a stronger inhibitory effect on voltage-gated sodium channel 1.5 (Nav1.5) than that of either TTX or LID alone. LID + TTX formulations were prepared with optimal stability containing 1 µg of TTX, 5 mg of LID, 6 mg of mannitol, and 4 mg of dextran-40 and then freeze dried. This formulation significantly delayed the onset and shortened the duration of arrhythmia induced by aconitine in rats. Arrhythmia-originated death was avoided by the combined formulation, with a decrease in the mortality rate from 64% to 0%. The data also suggests that the anti-arrhythmic effect of the combination was greater than that of either TTX or LID alone. This paper offers new approaches to develop effective medications against arrhythmias.


Assuntos
Antiarrítmicos/administração & dosagem , Arritmias Cardíacas/tratamento farmacológico , Lidocaína/administração & dosagem , Tetrodotoxina/administração & dosagem , Animais , Antiarrítmicos/farmacologia , Arritmias Cardíacas/mortalidade , Arritmias Cardíacas/fisiopatologia , Modelos Animais de Doenças , Combinação de Medicamentos , Estabilidade de Medicamentos , Excipientes/química , Feminino , Liofilização , Lidocaína/farmacologia , Masculino , Canal de Sódio Disparado por Voltagem NAV1.5/efeitos dos fármacos , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-Dawley , Tetrodotoxina/farmacologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/administração & dosagem , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia
5.
Trials ; 20(1): 588, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604475

RESUMO

BACKGROUND: Neuropathic pain is a common pain condition that has a major negative impact on health-related quality of life. However, despite decades of research, it remains difficult to treat neuropathic pain. Lacosamide is a sodium-channel blocker that is efficacious in animal models of neuropathic pain. In humans, its effect in neuropathic pain is inconclusive, based on inconsistent results and very large placebo responses. Previous trials have not used patient stratification or looked for predictors for response. METHODS: This study will be conducted as a multicenter, randomized, double-blind, placebo-controlled, parallel, phase 2, proof-of-concept, phenotype-stratified study. The study will enroll 108 patients with peripheral neuropathic pain who will be randomized to a 12-week treatment with lacosamide or placebo up to 400 mg/day in a 2:1 ratio. The primary objective is to compare the change in the mean value of the patients' daily ratings of average pain intensity from baseline to the last week of treatment in patients with and without the irritable nociceptor phenotype in the per-protocol population. A supportive objective is to compare the effect of lacosamide with that of placebo in the two phenotypes. Secondary and tertiary outcomes include the Patient Global Impression of Change, pain relief, presence of 30% and 50% pain reduction, sleep disturbance, depression, and anxiety. DISCUSSION: We will examine the concept of individualized therapy based on phenotyping, and expect that this study will provide important information on the usefulness of lacosamide in the treatment of peripheral neuropathic pain. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03777956 . Registered on 18 December 2018.


Assuntos
Analgésicos/uso terapêutico , Lacosamida/uso terapêutico , Neuralgia/tratamento farmacológico , Bloqueadores do Canal de Sódio Disparado por Voltagem/uso terapêutico , Analgésicos/efeitos adversos , Ensaios Clínicos Fase II como Assunto , Dinamarca , Método Duplo-Cego , Feminino , Humanos , Lacosamida/efeitos adversos , Masculino , Estudos Multicêntricos como Assunto , Neuralgia/diagnóstico , Medição da Dor , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Tempo , Resultado do Tratamento , Bloqueadores do Canal de Sódio Disparado por Voltagem/efeitos adversos
6.
Arch Gynecol Obstet ; 300(4): 941-955, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31435776

RESUMO

PURPOSE: The aim of the study was to evaluate the harmful effects of sepsis on the urogynecological tissues and the ability of Lacosamide (LCM) on Lipopolysaccharide (LPS)-induced cytokine production, oxidative stress and apoptotic pathways, in the experimental rat sepsis model. METHODS: Twenty-four female Wistar albino rats (12 months old) were divided into 3 groups as follows: control group (Group I) (0.1 ml/oral and i.p. saline, single dose), sepsis group (Group II) (5 mg/kg LPS, i.p. single dose) and sepsis + LCM group (Group III) (5 mg/kg LPS, i.p. single dose and 40 mg/kg LCM). Six hours after the last LPS administration, the animals were sacrificed. Subsequently, the analyses of urogenital tissues total oxidant/antioxidant status, histopathological and immunohistochemical analyses were performed. RESULTS: Total oxidant capacity (TOC) and oxidative stress index (OSI) values in the urogenital tissues were increased in the urogenital tissues in Group II [Total antioxidant capacity (TAC) was decreased] compared to group I (p < 0.05). LCM improved these values (p < 0.05). The immunohistochemical markers (Tumor Necrosis Factor-alpha (TNF-α), interleukin-1 beta (IL-1ß), heat shock protein 70 (HSP-70), C-reactive protein (CRP), Malondialdehyde (MDA) were significantly increased in Group II (p < 0.001). With the administration of LCM (Group III), the expressions of above-mentioned markers were markedly decreased (p < 0.001). Marked hyperemia and slight hemorrhages with neutrophil leukocyte infiltrations were seen histopathologically in Group II. LCM treatment ameliorated the pathological findings. CONCLUSION: These findings demonstrated that sepsis caused oxidative stress, apoptosis and inflammation in the urogenital tissues. We revealed that LCM ameliorated the damage caused by sepsis in urogenital tissue.


Assuntos
Lacosamida/uso terapêutico , Sepse/complicações , Sepse/tratamento farmacológico , Sistema Urogenital/efeitos dos fármacos , Sistema Urogenital/patologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/uso terapêutico , Animais , Feminino , Lacosamida/farmacologia , Masculino , Ratos , Ratos Wistar , Sepse/patologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia
7.
Pharm Res ; 36(9): 137, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31332533

RESUMO

PURPOSE: Pitt Hopkins Syndrome (PTHS) is a rare genetic disorder caused by mutations of a specific gene, transcription factor 4 (TCF4), located on chromosome 18. PTHS results in individuals that have moderate to severe intellectual disability, with most exhibiting psychomotor delay. PTHS also exhibits features of autistic spectrum disorders, which are characterized by the impaired ability to communicate and socialize. PTHS is comorbid with a higher prevalence of epileptic seizures which can be present from birth or which commonly develop in childhood. Attenuated or absent TCF4 expression results in increased translation of peripheral ion channels Kv7.1 and Nav1.8 which triggers an increase in after-hyperpolarization and altered firing properties. METHODS: We now describe a high throughput screen (HTS) of 1280 approved drugs and machine learning models developed from this data. The ion channels were expressed in either CHO (KV7.1) or HEK293 (Nav1.8) cells and the HTS used either 86Rb+ efflux (KV7.1) or a FLIPR assay (Nav1.8). RESULTS: The HTS delivered 55 inhibitors of Kv7.1 (4.2% hit rate) and 93 inhibitors of Nav1.8 (7.2% hit rate) at a screening concentration of 10 µM. These datasets also enabled us to generate and validate Bayesian machine learning models for these ion channels. We also describe a structure activity relationship for several dihydropyridine compounds as inhibitors of Nav1.8. CONCLUSIONS: This work could lead to the potential repurposing of nicardipine or other dihydropyridine calcium channel antagonists as potential treatments for PTHS acting via Nav1.8, as there are currently no approved treatments for this rare disorder.


Assuntos
Di-Hidropiridinas/farmacologia , Reposicionamento de Medicamentos/métodos , Hiperventilação/tratamento farmacológico , Deficiência Intelectual/tratamento farmacológico , Canal de Potássio KCNQ1/antagonistas & inibidores , Canal de Sódio Disparado por Voltagem NAV1.8/metabolismo , Bloqueadores dos Canais de Potássio/farmacologia , Bloqueadores dos Canais de Sódio/farmacologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Animais , Teorema de Bayes , Células CHO , Cricetulus , Di-Hidropiridinas/química , Facies , Células HEK293 , Humanos , Canal de Potássio KCNQ1/metabolismo , Aprendizado de Máquina , Bloqueadores dos Canais de Potássio/química , Bibliotecas de Moléculas Pequenas/química , Bloqueadores dos Canais de Sódio/química , Relação Estrutura-Atividade , Bloqueadores do Canal de Sódio Disparado por Voltagem/química
8.
Mar Drugs ; 17(7)2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31269696

RESUMO

Cyclic µ-conotoxin PIIIA, a potent blocker of skeletal muscle voltage-gated sodium channel NaV1.4, is a 22mer peptide stabilized by three disulfide bonds. Combining electrophysiological measurements with molecular docking and dynamic simulations based on NMR solution structures, we investigated the 15 possible 3-disulfide-bonded isomers of µ-PIIIA to relate their blocking activity at NaV1.4 to their disulfide connectivity. In addition, three µ-PIIIA mutants derived from the native disulfide isomer, in which one of the disulfide bonds was omitted (C4-16, C5-C21, C11-C22), were generated using a targeted protecting group strategy and tested using the aforementioned methods. The 3-disulfide-bonded isomers had a range of different conformational stabilities, with highly unstructured, flexible conformations with low or no channel-blocking activity, while more constrained molecules preserved 30% to 50% of the native isomer's activity. This emphasizes the importance and direct link between correct fold and function. The elimination of one disulfide bond resulted in a significant loss of blocking activity at NaV1.4, highlighting the importance of the 3-disulfide-bonded architecture for µ-PIIIA. µ-PIIIA bioactivity is governed by a subtle interplay between an optimally folded structure resulting from a specific disulfide connectivity and the electrostatic potential of the conformational ensemble.


Assuntos
Conotoxinas/farmacocinética , Canal de Sódio Disparado por Voltagem NAV1.4/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Conotoxinas/química , Dissulfetos/química , Isomerismo , Simulação de Acoplamento Molecular , Conformação Proteica , Eletricidade Estática , Relação Estrutura-Atividade , Bloqueadores do Canal de Sódio Disparado por Voltagem/química
9.
J Toxicol Sci ; 44(7): 441-457, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31270301

RESUMO

The objective of this study is to assess the response of telemetered common marmosets to multiple cardiac ion channel inhibitors and to clarify the usefulness of this animal model in evaluating the effects of drug candidates on electrocardiogram (ECG). Six multiple cardiac ion channel inhibitors (sotalol, astemizole, flecainide, quinidine, verapamil and terfenadine) were orally administered to telemetered common marmosets and changes in QTc, PR interval and QRS duration were evaluated. Drugs plasma levels were determined to compare the sensitivity in common marmosets to that in humans. QTc prolongation was observed in the marmosets dosed with sotalol, astemizole, flecainide, quinidine, verapamil and terfenadine. PR prolongation was noted after flecainide and verapamil administration, and QRS widening occurred following treatment with flecainide and quinidine. Drugs plasma levels associated with ECG changes in marmosets were similar to those in humans, except for verapamil-induced QTc prolongation. Verapamil-induced change is suggested due to body temperature decrease. These results indicate that telemetered common marmoset is a useful animal for evaluation of the ECG effects of multiple cardiac ion channel inhibitors and the influence of body temperature change should be considered in the assessment.


Assuntos
Astemizol/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Callithrix , Eletrocardiografia/efeitos dos fármacos , Flecainida/farmacologia , Modelos Animais , Quinidina/farmacologia , Medição de Risco/métodos , Sotalol/farmacologia , Telemetria , Terfenadina/farmacologia , Verapamil/farmacologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Animais , Astemizol/sangue , Temperatura Corporal/fisiologia , Bloqueadores dos Canais de Cálcio/sangue , Flecainida/sangue , Masculino , Quinidina/sangue , Sotalol/sangue , Terfenadina/sangue , Verapamil/sangue , Bloqueadores do Canal de Sódio Disparado por Voltagem/sangue
10.
Chin J Nat Med ; 17(6): 413-423, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31262454

RESUMO

Isoflavones are widely consumed by people around the world in the form of soy products, dietary supplements and drugs. Many isoflavones or related crude extracts have been reported to exert pain-relief activities, but the mechanism remains unclear. Voltage-gated sodium channels (VGSCs) play important roles in excitability of pain sensing neurons and many of them are important nociceptors. Here, we report that several isoflavones including 3'-methoxydaidzein (3MOD), genistein (GEN) and daidzein (DAI) show abilities to block VGSCs and thus to attenuate chemicals and heat induced acute pain or chronic constriction injury (CCI) induced pain hypersensitivity in mice. Especially, 3MOD shows strong analgesic potential without inducing addiction through inhibiting subtypes NaV1.7, NaV1.8 and NaV1.3 with the IC50 of 181 ± 14, 397 ± 26, and 505 ± 46 nmol·L-1, respectively, providing a promising compound or parent structure for the treatment of pain pathologies. This study reveals a pain-alleviating mechanism of dietary isoflavones and may provide a convenient avenue to alleviate pain.


Assuntos
Analgésicos/administração & dosagem , Isoflavonas/administração & dosagem , Dor/tratamento farmacológico , Bloqueadores do Canal de Sódio Disparado por Voltagem/administração & dosagem , Canais de Sódio Disparados por Voltagem/metabolismo , Analgésicos/química , Animais , Humanos , Isoflavonas/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dor/genética , Dor/metabolismo , Canais de Sódio Disparados por Voltagem/genética
11.
Biol Pharm Bull ; 42(7): 1226-1229, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31257298

RESUMO

Flecainide, an anti-arrhythmic drug, undergoes renal excretion through active renal tubular secretion in addition to passive glomerular filtration. The contribution of renal uptake and efflux transporters in active renal tubular secretion of flecainide remains unclear except that flecainide is a substrate of human multidrug resistance protein 1 (MDR1). To elucidate renal efflux and uptake transporters involved with active renal tubular secretion of flecainide, we conducted in vitro interaction studies of flecainide using organic cation transporter 2 (OCT2), multidrug and toxin extrusion (MATE) 1, and MATE2-K. Uptake transporter inhibition assays using hOCT2-Chinese hamster ovary (CHO), hMATE1-CHO, and hMATE2-K-Madin Darby canine kidney strain II (MDCKII) cells revealed that flecainide (2.5 µM) inhibited hMATE1-mediated transport by 40% with an IC50 value of 6.7 µM; however, it showed no or weak inhibitory effects on hOCT2- and hMATE2-K-mediated transport. For investigating flecainide as a substrate of hMATE1, the accumulation of flecainide in hMATE1-CHO was compared with that in control cells. Uptake transporter substrate assay revealed that flecainide (1 µM) showed 1.11-fold accumulation though the hMATE1-related active transport was significantly decreased in the presence of quinidine (42.0 ± 23.9 vs. 11.8 ± 4.1 pmol/mg in transfected cells; p < 0.05). These results suggest that flecainide is a weak substrate of hMATE1, which is involved in the renal tubular secretion of cationic drugs, and hMATE1 may be less important in the pharmacokinetic drug-drug interaction for renal excretion of flecainide. However, in vivo drug-drug interaction studies of flecainide with substrates of hMATE1 may be needed because flecainide has the potential to inhibit hMATE1.


Assuntos
Flecainida/farmacologia , Rim/metabolismo , Proteínas de Transporte de Cátions Orgânicos/metabolismo , Transportador 2 de Cátion Orgânico/metabolismo , Eliminação Renal , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Animais , Células CHO , Cricetulus , Cães , Interações Medicamentosas , Células Madin Darby de Rim Canino , Proteínas de Transporte de Cátions Orgânicos/genética , Transportador 2 de Cátion Orgânico/genética
12.
Int Heart J ; 60(4): 979-982, 2019 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-31257342

RESUMO

Congenital long QT syndrome (LQTS) is a cardiac channelopathy that leads to the prolongation of the QT interval. This prolongation can lead to ventricular tachyarrhythmia, syncope, and sudden cardiac death. There are various types of LQTS. Treatment of LQT1 and LQT2 is mainly based on antiadrenergic therapy. LQT3, on the other hand, is a result of a mutation of the SCN5A gene, which encodes the sodium channels. In this type, patients are sensitive to vagal stimuli and episodes tend to occur at rest. Sodium channel blocking compounds, such as ranolazine, mexiletine, and flecainide, have been found to be effective in selective mutations.In this case report, we report the case of a child with congenital LQT3 (V411M) who presented first with sudden cardiac death and three weeks later with an implantable cardioverter defibrillator storm. Knowing the specific mutation and understanding the mechanism at the molecular level through an in vitro study yielded a clinically meaningful result. The patient's arrhythmia burden was totally eliminated following successful treatment with flecainide.


Assuntos
DNA/genética , Eletrocardiografia , Flecainida/uso terapêutico , Síndrome do QT Longo/tratamento farmacológico , Mutação , Canal de Sódio Disparado por Voltagem NAV1.5/genética , Criança , Análise Mutacional de DNA , Feminino , Humanos , Síndrome do QT Longo/diagnóstico , Síndrome do QT Longo/genética , Canal de Sódio Disparado por Voltagem NAV1.5/metabolismo , Bloqueadores do Canal de Sódio Disparado por Voltagem/uso terapêutico
13.
Drug Dev Res ; 80(6): 846-856, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31301190

RESUMO

Nalbuphine (NAL) is recognized as a mixer with the κ-opioid receptor agonist and the µ-opioid receptor antagonist. However, whether this drug causes any modifications in neuronal ionic currents is unclear. The effects of NAL on ionic currents in mHippoE-14 hippocampal neurons were investigated. In the whole-cell current recordings, NAL suppressed the peak amplitude of voltage-gated Na+ current (INa ) with an IC50 value of 1.9 µM. It shifted the steady-state inactivation curve of peak INa to the hyperpolarized potential, suggesting that there is the voltage dependence of NAL-mediated inhibition of peak INa . In continued presence of NAL, subsequent application of either dynorphin A1-13 (1 µM) or naloxone (30 µM) failed to modify its suppression of peak INa . Tefluthrin (Tef; 10 µM), a pyrethroid known to activate INa , increased peak INa with slowed current inactivation; however, further application of NAL suppressed Tef-mediated suppression of peak INa followed by an additional slowing of current inactivation. In addition, NAL suppressed the amplitude of M-type K+ current [IK(M) ] with an IC50 value of 5.7 µM, while it slightly suppressed erg-mediated and delayed-rectifier K+ currents. In the inside-out current recordings, NAL failed to modify the activity of large-conductance Ca2+ -activated K+ channels. In differentiated NG108-15 neuronal cells, NAL also suppressed the peak INa , and subsequent addition of Tef reversed NAL-induced suppression of INa . Our study highlights the evidence that in addition to modulate opioid receptors, NAL has the propensity to interfere with ionic currents including INa and IK(M) , thereby influencing the functional activities of central neurons.


Assuntos
Analgésicos Opioides/farmacologia , Canais de Potássio de Retificação Tardia/antagonistas & inibidores , Canais de Potássio Éter-A-Go-Go/antagonistas & inibidores , Nalbufina/farmacologia , Neurônios/efeitos dos fármacos , Receptores Opioides kappa/agonistas , Receptores Opioides mu/antagonistas & inibidores , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Animais , Linhagem Celular , Canais de Potássio de Retificação Tardia/fisiologia , Canais de Potássio Éter-A-Go-Go/fisiologia , Canais de Potássio Ativados por Cálcio de Condutância Alta/fisiologia , Camundongos , Neurônios/fisiologia
14.
Pain ; 160(8): 1766-1780, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31335646

RESUMO

Pain is the leading cause of disability in the developed world but remains a poorly treated condition. Specifically, postsurgical pain continues to be a frequent and undermanaged condition. Here, we investigate the analgesic potential of pharmacological NaV1.7 inhibition in a mouse model of acute postsurgical pain, based on incision of the plantar skin and underlying muscle of the hind paw. We demonstrate that local and systemic treatment with the selective NaV1.7 inhibitor µ-theraphotoxin-Pn3a is effectively antiallodynic in this model and completely reverses mechanical hypersensitivity in the absence of motor adverse effects. In addition, the selective NaV1.7 inhibitors ProTx-II and PF-04856264 as well as the clinical candidate CNV1014802 also reduced mechanical allodynia. Interestingly, co-administration of the opioid receptor antagonist naloxone completely reversed analgesic effects of Pn3a, indicating an involvement of endogenous opioids in the analgesic activity of Pn3a. In addition, we found superadditive antinociceptive effects of subtherapeutic Pn3a doses not only with the opioid oxycodone but also with the GABAB receptor agonist baclofen. Transcriptomic analysis of gene expression changes in dorsal root ganglia of mice after surgery did not reveal any changes in mRNA expression of endogenous opioids or opioid receptors; however, several genes involved in pain, including Runx1 (Runt related transcription factor 1), Cacna1a (CaV2.1), and Cacna1b (CaV2.2), were downregulated. In summary, these findings suggest that pain after surgery can be successfully treated with NaV1.7 inhibitors alone or in combination with baclofen or opioids, which may present a novel and safe treatment strategy for this frequent and poorly managed condition.


Assuntos
Analgésicos Opioides/uso terapêutico , Baclofeno/uso terapêutico , Agonistas dos Receptores de GABA-B/uso terapêutico , Hiperalgesia/tratamento farmacológico , Dor Pós-Operatória/tratamento farmacológico , Bloqueadores do Canal de Sódio Disparado por Voltagem/uso terapêutico , Analgésicos Opioides/farmacologia , Animais , Baclofeno/farmacologia , Modelos Animais de Doenças , Sinergismo Farmacológico , Agonistas dos Receptores de GABA-B/farmacologia , Masculino , Camundongos , Medição da Dor , Limiar da Dor/efeitos dos fármacos , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia
15.
Toxins (Basel) ; 11(6)2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31234412

RESUMO

Phlotoxin-1 (PhlTx1) is a peptide previously identified in tarantula venom (Phlogius species) that belongs to the inhibitory cysteine-knot (ICK) toxin family. Like many ICK-based spider toxins, the synthesis of PhlTx1 appears particularly challenging, mostly for obtaining appropriate folding and concomitant suitable disulfide bridge formation. Herein, we describe a procedure for the chemical synthesis and the directed sequential disulfide bridge formation of PhlTx1 that allows for a straightforward production of this challenging peptide. We also performed extensive functional testing of PhlTx1 on 31 ion channel types and identified the voltage-gated sodium (Nav) channel Nav1.7 as the main target of this toxin. Moreover, we compared PhlTx1 activity to 10 other spider toxin activities on an automated patch-clamp system with Chinese Hamster Ovary (CHO) cells expressing human Nav1.7. Performing these analyses in reproducible conditions allowed for classification according to the potency of the best natural Nav1.7 peptide blockers. Finally, subsequent in vivo testing revealed that intrathecal injection of PhlTx1 reduces the response of mice to formalin in both the acute pain and inflammation phase without signs of neurotoxicity. PhlTx1 is thus an interesting toxin to investigate Nav1.7 involvement in cellular excitability and pain.


Assuntos
Analgésicos/isolamento & purificação , Peptídeos/isolamento & purificação , Venenos de Aranha/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/isolamento & purificação , Sequência de Aminoácidos , Analgésicos/química , Analgésicos/farmacologia , Analgésicos/uso terapêutico , Animais , Células CHO , Cricetulus , Feminino , Formaldeído , Camundongos Endogâmicos C57BL , Canal de Sódio Disparado por Voltagem NAV1.7/fisiologia , Oócitos , Dor/induzido quimicamente , Dor/tratamento farmacológico , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/uso terapêutico , Dobramento de Proteína , Aranhas , Bloqueadores do Canal de Sódio Disparado por Voltagem/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/uso terapêutico , Xenopus laevis
16.
ACS Chem Biol ; 14(4): 806-818, 2019 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-30875193

RESUMO

Drug discovery research on new pain targets with human genetic validation, including the voltage-gated sodium channel NaV1.7, is being pursued to address the unmet medical need with respect to chronic pain and the rising opioid epidemic. As part of early research efforts on this front, we have previously developed NaV1.7 inhibitory peptide-antibody conjugates with tarantula venom-derived GpTx-1 toxin peptides with an extended half-life (80 h) in rodents but only moderate in vitro activity (hNaV1.7 IC50 = 250 nM) and without in vivo activity. We identified the more potent peptide JzTx-V from our natural peptide collection and improved its selectivity against other sodium channel isoforms through positional analogueing. Here we report utilization of the JzTx-V scaffold in a peptide-antibody conjugate and architectural variations in the linker, peptide loading, and antibody attachment site. We found conjugates with 100-fold improved in vitro potency relative to those of complementary GpTx-1 analogues, but pharmacokinetic and bioimaging analyses of these JzTx-V conjugates revealed a shorter than expected plasma half-life in vivo with accumulation in the liver. In an attempt to increase circulatory serum levels, we sought the reduction of the net +6 charge of the JzTx-V scaffold while retaining a desirable NaV in vitro activity profile. The conjugate of a JzTx-V peptide analogue with a +2 formal charge maintained NaV1.7 potency with 18-fold improved plasma exposure in rodents. Balancing the loss of peptide and conjugate potency associated with the reduction of net charge necessary for improved target exposure resulted in a compound with moderate activity in a NaV1.7-dependent pharmacodynamic model but requires further optimization to identify a conjugate that can fully engage NaV1.7 in vivo.


Assuntos
Imunoconjugados , Canal de Sódio Disparado por Voltagem NAV1.7/metabolismo , Peptídeos/química , Venenos de Aranha/química , Bloqueadores do Canal de Sódio Disparado por Voltagem , Animais , Anticorpos/química , Descoberta de Drogas , Humanos , Imunoconjugados/química , Imunoconjugados/farmacocinética , Masculino , Camundongos , Terapia de Alvo Molecular , Canal de Sódio Disparado por Voltagem NAV1.7/imunologia , Peptídeos/farmacocinética , Venenos de Aranha/farmacocinética , Bloqueadores do Canal de Sódio Disparado por Voltagem/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacocinética
17.
Acta Neurol Belg ; 119(3): 423-430, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30840220

RESUMO

The objective of this study was to evaluate the tolerability and efficacy of lacosamide (LCM) in residential patients at our epilepsy centre. We assessed retrospectively 80 patients (mean age 36.2 years, range 18-63 years; 29 female) with intellectual disability (ID) and drug-resistant epilepsy using an industry-independent, non-interventional study design based on standardised seizure records. Evaluation, including calculation of retention rate, was carried out for the intervals 3-6, 9-12 and 21-24 months after LCM initiation. The Clinical Global Impression scale (CGI) was used to allow assessment of qualitative changes in seizure severity and clinical status. CGI improved for 61% of the patients. The responder rate was 48%; ten patients (13%) became seizure free. The response was not related to the degree of ID. The retention rates after 12 and 24 months were 71% and 65%, and were significantly lower in patients taking other sodium-channel blockers (SCBs; 76% vs. 55%). The occurrence of adverse events (AEs) was related to the administration of concomitant SCBs (48% with SCBs vs. 26% without). Sedation (15%), ataxia (13%), vertigo (11%), and nausea (9%) were the commonest AEs. While 60% of our patients had concomitant psychiatric diagnosis, we found no relevant effect of this on challenging behaviour. Adjunctive LCM may provide an antiepileptic treatment option for patients with ID with or without additional psychiatric diagnosis. The occurrence of AEs and the LCM retention rate were affected by concomitant SCB use but not by psychiatric comorbidity.


Assuntos
Anticonvulsivantes/farmacologia , Epilepsia Resistente a Medicamentos/tratamento farmacológico , Deficiência Intelectual , Lacosamida/farmacologia , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Adolescente , Adulto , Anticonvulsivantes/efeitos adversos , Comorbidade , Epilepsia Resistente a Medicamentos/epidemiologia , Quimioterapia Combinada , Feminino , Seguimentos , Humanos , Deficiência Intelectual/epidemiologia , Lacosamida/efeitos adversos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Bloqueadores do Canal de Sódio Disparado por Voltagem/efeitos adversos , Adulto Jovem
18.
PLoS One ; 14(3): e0213751, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30856233

RESUMO

Voltage-gated sodium channels (NaVs) are key therapeutic targets for pain, epilepsy and cardiac arrhythmias. Here we describe the development of a no-wash fluorescent sodium influx assay suitable for high-throughput screening and characterization of novel drug leads. Addition of red-violet food dyes (peak absorbance range 495-575 nm) to assays in HEK293 cells heterologously expressing hNaV1.1-1.8 effectively quenched background fluorescence of the sodium indicator dye Asante NaTRIUM Green-2 (ANG-2; peak emission 540 nm), negating the need for a wash step. Ponceau 4R (1 mM) was identified as a suitable quencher, which had no direct effect on NaV channels as assessed by patch-clamp experiments, and did not alter the pharmacology of the NaV1.1-1.7 activator veratridine (EC50 10-29 µM) or the NaV1.1-1.8 inhibitor tetracaine (IC50's 6-66 µM). In addition, we also identified that the food dyes Ponceau 4R, Brilliant Black BN, Allura Red and Amaranth are effective at quenching the background fluorescence of the calcium indicator dyes fluo-4, fura-2 and fura-5F, identifying them as potential inexpensive alternatives to no-wash calcium ion indicator kits. In summary, we have developed a no-wash fluorescent sodium influx assay suitable for high-throughput screening based on the sodium indicator dye ANG-2 and the quencher Ponceau 4R.


Assuntos
Ensaios de Triagem em Larga Escala/métodos , Sódio/metabolismo , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Células HEK293 , Humanos , Técnicas de Patch-Clamp , Sódio/análise , Espectrometria de Fluorescência , Tetracaína/química , Tetracaína/metabolismo , Veratridina/química , Veratridina/metabolismo , Agonistas do Canal de Sódio Disparado por Voltagem/química , Agonistas do Canal de Sódio Disparado por Voltagem/metabolismo , Bloqueadores do Canal de Sódio Disparado por Voltagem/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/metabolismo , Canais de Sódio Disparados por Voltagem/química , Canais de Sódio Disparados por Voltagem/metabolismo
19.
J Pharmacol Exp Ther ; 369(2): 200-211, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30792243

RESUMO

Volatile anesthetics depress neurotransmitter release in a brain region- and neurotransmitter-selective manner by unclear mechanisms. Voltage-gated sodium channels (Navs), which are coupled to synaptic vesicle exocytosis, are inhibited by volatile anesthetics through reduction of peak current and modulation of gating. Subtype-selective effects of anesthetics on Nav might contribute to observed neurotransmitter-selective anesthetic effects on release. We analyzed anesthetic effects on Na+ currents mediated by the principal neuronal Nav subtypes Nav1.1, Nav1.2, and Nav1.6 heterologously expressed in ND7/23 neuroblastoma cells using whole-cell patch-clamp electrophysiology. Isoflurane at clinically relevant concentrations induced a hyperpolarizing shift in the voltage dependence of steady-state inactivation and slowed recovery from fast inactivation in all three Nav subtypes, with the voltage of half-maximal steady-state inactivation significantly more positive for Nav1.1 (-49.7 ± 3.9 mV) than for Nav1.2 (-57.5 ± 1.2 mV) or Nav1.6 (-58.0 ± 3.8 mV). Isoflurane significantly inhibited peak Na+ current (I Na) in a voltage-dependent manner: at a physiologically relevant holding potential of -70 mV, isoflurane inhibited peak I Na of Nav1.2 (16.5% ± 5.5%) and Nav1.6 (18.0% ± 7.8%), but not of Nav1.1 (1.2% ± 0.8%). Since Nav subtypes are differentially expressed both between neuronal types and within neurons, greater inhibition of Nav1.2 and Nav1.6 compared with Nav1.1 could contribute to neurotransmitter-selective effects of isoflurane on synaptic transmission.


Assuntos
Anestésicos Gerais/farmacologia , Isoflurano/farmacologia , Neurônios/citologia , Neurônios/efeitos dos fármacos , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Animais , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Cinética , Neurônios/metabolismo , Neurotransmissores/metabolismo , Sinapses/efeitos dos fármacos , Sinapses/fisiologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA