1,720,991 research outputs found
Effects of Benzothiazolamines on Voltage-Gated Sodium Channels
No full textBenzothiazole is a versatile fused heterocycle that aroused much interest in drug discovery as anticonvulsant, neuroprotective, analgesic, anti-inflammatory, antimicrobial, and anticancer. Two benzothiazolamines, riluzole and lubeluzole, are known blockers of voltage-gated sodium (Nav) channels. Riluzole is clinically used as a neuroprotectant in amyotrophic lateral sclerosis. Inhibition of Navchannels by riluzole is voltage-dependent due to preferential binding to inactivated sodium channels. Yet the drug exerts little use-dependent block, probably because it lacks protonable amine. One important property is riluzole ability to inhibit persistent Na+currents, which likely contributes to its neuroprotective activity. Lubeluzole showed promising neuroprotective effects in animal stroke models, but failed to show benefits in acute ischemic stroke in humans. One important concern is its propensity to prolong the cardiac QT interval, due to hERG K+channel block. Lubeluzole very potently inhibits Navchannels in a voltage- and use-dependent manner, due to its great preferential affinity for inactivated channels and the presence of a protonable amine group. Patch-clamp experiments suggest that the binding sites of both drugs overlap the local anesthetic receptor within the ion-conducting pathway. Riluzole and lubeluzole displayed very potent antimyotonic activity in a rat model of myotonia, a pathological skeletal muscle condition characterized by high-frequency runs of action potentials. Such results well support the repurposing of riluzole as an antimyotonic drug, allowing the launch of a pilot study in myotonic patients. Riluzole, lubeluzole, and new Navchannel blockers built on the benzothiazolamine scaffold will certainly continue to be investigated for possible clinical applications
Ion Channel Involvement in Tumor Drug Resistance
Full text linkOver 90% of deaths in cancer patients are attributed to tumor drug resistance. Resistance to therapeutic agents can be due to an innate property of cancer cells or can be acquired during chemotherapy. In recent years, it has become increasingly clear that regulation of membrane ion channels is an important mechanism in the development of chemoresistance. Here, we review the contribution of ion channels in drug resistance of various types of cancers, evaluating their potential in clinical management. Several molecular mechanisms have been proposed, including evasion of apoptosis, cell cycle arrest, decreased drug accumulation in cancer cells, and activation of alternative escape pathways such as autophagy. Each of these mechanisms leads to a reduction of the therapeutic efficacy of administered drugs, causing more difficulty in cancer treatment. Thus, targeting ion channels might represent a good option for adjuvant therapies in order to counteract chemoresistance development
Pharmacological therapy of non-dystrophic myotonias
Full text linkObjectives. Non-dystrophic myotonias (NDM) are rare diseases due to mutations in the voltage-gated sodium (Nav1.4) and chloride (ClC-1) channels expressed in skeletal muscle fibers. We provide an up-to-date review of pharmacological treatments available for NDM patients and experimental studies aimed at identifying alternative treatments and at better understanding the mechanisms of actions. Methods. Literature research was performed using PubMed and ClinicalTrial.gov. Results. Today, the sodium channel blocker mexiletine is the drug of choice for treatment of NDM. Alternative drugs include other sodium channel blockers and the carbonic anhydrase inhibitor acetazolamide. Preclinical studies suggest that activators of ClC-1 channels or voltage-gated potassium channels may have antimyotonic potential. Conclusions. An increasing number of antimyotonic drugs would help to design a precision therapy to address personalized treatment of myotonic individuals
NSAIDS AS MODULATORS OF CATION CHANNELS: FENAMATES REPURPOSING IN CHANNELOPATHIES
No full text: Cationic ion channels are transmembrane proteins that regulate the flux of cations (potassium, sodium, and calcium) across cell membrane, playing a pivotal role in many cellular functions. Disruptions of their activity can lead to the so-called genetic or acquired channelopathies, a heterogeneous group of diseases that affect multiple human systems. Fenamates, a class of Nonsteroidal Anti-Inflammatory Drugs (NSAIDs), has recently emerged as modulators of cationic ion channels highlighting the possibility of their repurposing for the treatment ion channel-related disorders, such as channelopathies, chronic pain, epilepsy, cardiac arrhythmias and cancers. In this review, we describe the ability of fenamates (i.e. niflumic, flufenamic, mefenamic, meclofenamic and tolfenamic acids) to differentially modulate the activity of cationic ion channels. Overall, preclinical and clinical studies suggest that fenamates represent a promising class of compounds for drug repurposing and for the development of new molecules, offering novel therapeutic opportunities for patients affected by ion channel-related disorders
Drug repurposing in skeletal muscle ion channelopathies
No full textSkeletal muscle ion channelopathies are rare genetic diseases mainly characterized by myotonia (muscle stiffness) or periodic paralysis (muscle weakness). Here, we reviewed the available therapeutic options in non-dystrophic myotonias (NDM) and periodic paralyses (PP), which consists essentially in drug repositioning to address stiffness or weakness attacks. Empirical use followed by successful randomized clinical trials eventually led to the orphan drug designation and marketing authorization granting of mexiletine for NDM and dichlorphenamide for PP. Yet, these treatments neither consider the genetic cause of the diseases nor address the individual variability in drug response. Thus, ongoing research aims at the identification of repurposed drugs alternative to mexiletine and dichlorphenamide to allow personalization of treatment. This review highlights how drug repurposing may represent an efficient strategy in rare diseases, allowing reduction of drug development time and costs in a context in which the return on investment may be particularly challenging
Skeletal muscle ClC-1 chloride channels in health and diseases
No full textIn 1970, the study of the pathomechanisms underlying myotonia in muscle fibers isolated from myotonic goats highlighted the importance of chloride conductance for skeletal muscle function; 20 years later, the human ClC-1 chloride channel has been cloned; last year, the crystal structure of human protein has been solved. Over the years, the efforts of many researchers led to significant advances in acknowledging the role of ClC-1 in skeletal muscle physiology and the mechanisms through which ClC-1 dysfunctions lead to impaired muscle function. The wide spectrum of pathophysiological conditions associated with modification of ClC-1 activity, either as the primary cause, such as in myotonia congenita, or as a secondary adaptive mechanism in other neuromuscular diseases, supports the idea that ClC-1 is relevant to preserve not only for skeletal muscle excitability, but also for skeletal muscle adaptation to physiological or harmful events. Improving this understanding could open promising avenues toward the development of selective and safe drugs targeting ClC-1, with the aim to restore normal muscle function. This review summarizes the most relevant research on ClC-1 channel physiology, associated diseases, and pharmacology
Pleiotropic Effects of the NSAID Fenamates on Chloride Channels: Opportunity for Ion Channelopathies?
Full text linkChloride channels are involved in many cellular processes, including cell volume regulation, modulation of cell excitability, and electrolyte and water secretion. Mutations of these proteins are associated with heterogeneous diseases such as myotonia, cystic fibrosis, epilepsy, deafness, lysosomal storage disease, and various kinds of renal and ophthalmic dysfunctions, also known as channelopathies. Thus, drugs targeting chloride channels may have important therapeutic applications. In this context, fenamates, commonly used for their anti-inflammatory properties, have been explored for drug repurposing in chloride channelopathies thanks to their ability to modulate multiple chloride channels. This narrative review resumes the effects of niflumic acid (NFA), flufenamic acid (FFA), mefenamic acid (MFA), meclofenamic acid (MCFA), and tolfenamic acid (TFA) on different types of chloride channel. It emerges that fenamates have a wide spectrum of activities on these channels that vary depending on multiple factors like channel isoforms, extracellular and intracellular conditions, and cell and tissue types. They may also exhibit both activating and inhibitory effects depending on their concentration. Therefore, thanks to their variegated modulatory activity on chloride channels, fenamates might be considered promising lead compounds for the development of new drug candidates that can target these altered channels involved in channelopathies. Trial Registration: EudraCT number: 2021-000708-39; ClinicalTrials.gov identifier: NCT029930005 and NCT02429570
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Buprenorphine may be effective for treatment of paramyotonia congenita
No full textIntroduction/Aims: Paramyotonia congenita (PMC) is a skeletal muscle sodium channelopathy characterized by paradoxical myotonia, cold sensitivity, and exercise/cold-induced paralysis. Treatment with sodium-channel–blocking antiarrhythmic agents may expose patients to a risk of arrhythmia or may be poorly tolerated or ineffective. In this study we explored the effectiveness of non-antiarrhythmic sodium-channel blockers in two patients with PMC. Methods: Earlier treatment with mexiletine was discontinued for gastrointestinal side effects in one of the patients and lack of clinical benefit in the other. One patient received lacosamide, ranolazine, and buprenorphine, and the other was given buprenorphine only. Drug efficacy was assessed by clinical scores, timed tests, and by long and short exercise tests. Results: In both patients, buprenorphine improved pain scores by at least 50%, stiffness and weakness levels, and handgrip/eyelid-opening times. The fall in compound muscle action potential (CMAP) during short exercise normalized in both patients at baseline, and improved after cooling. During long exercise, one patient showed an earlier recovery of CMAP, and the other patient had a less severe decrease (<60%). With buprenorphine, the fall in CMAP induced by cooling normalized in one patient (from −72% to −4%) and improved (from −49% to −37%) in the other patient. Discussion: Buprenorphine showed promising results for the treatment of exercise-induced paralysis and cold intolerance in the two patients assessed. The exercise test may be useful for quantitative assessment of treatment response. Further studies on a larger number of patients, under carefully controlled conditions, should be considered to address the effectiveness and long-term tolerability of this therapeutic option
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