Direct Inhibition of BK Channels by Cannabidiol, One of the Principal Therapeutic Cannabinoids Derived from .

Cannabidiol (CBD), one of the main bioactive compounds, is utilized in the treatment of major epileptic syndromes. Its efficacy can be attributed to a multimodal mechanism of action that includes, as potential targets, several types of ion channels. In the brain, CBD reduces the firing frequency in rat hippocampal neurons, partly prolonging the duration of action potentials, suggesting a potential blockade of voltage-operated K channels.

A Combined Ligand- and Structure-Based Virtual Screening To Identify Novel NaV1.2 Blockers: In Vitro Patch Clamp Validation and In Vivo Anticonvulsant Activity.

Epilepsy is a neurological disorder characterized by recurrent seizures that arise from abnormal electrical activity in the brain. Voltage-gated sodium channels (NaVs), responsible for the initiation and propagation of action potentials in neurons, play a critical role in the pathogenesis of epilepsy. This study sought to discover potential anticonvulsant compounds that interact with NaVs, specifically, the brain subtype hNaV1.

Novel Dimeric hHv1 Model and Structural Bioinformatic Analysis Reveal an ATP-Binding Site Resulting in a Channel Activating Effect.

The human voltage-gated proton channel (hHv1) is a highly selective ion channel codified by the gene. It plays a fundamental role in several physiological processes such as innate and adaptive immunity, insulin secretion, and sperm capacitation. Moreover, in humans, a higher hHv1 expression/function has been reported in several types of cancer cells.

Structure-Based Virtual Screening Identifies Novobiocin, Montelukast, and Cinnarizine as TRPV1 Modulators with Anticonvulsant Activity .

The transient receptor potential vanilloid 1 (TRPV1) receptor is a nonselective cation channel, known to be involved in the regulation of many important physiological and pathological processes. In the last few years, it has been proposed as a promising target to develop novel anticonvulsant compounds. However, thermoregulatory effects associated with the channel inhibition have hampered the path for TRPV1 antagonists to become marketed drugs.

Differential expression of the long and truncated Hv1 isoforms in breast-cancer cells.

Metabolic reprogramming of cancer cells results in a high production of acidic substances that must be extruded to maintain tumor-cell viability. The voltage-gated proton channel (Hv1) mediates highly selective effluxes of hydronium-ion (H ) that prevent deleterious cytoplasmic acidification. In the work described here, we demonstrated for the first time that the amino-terminal-truncated isoform of Hv1 is more highly expressed in tumorigenic breast-cancer-cell lines than in nontumorigenic breast cells.

Regulation of extracellular ATP of human erythrocytes treated with α-hemolysin. Effects of cell volume, morphology, rheology and hemolysis.

Alpha-hemolysin (HlyA) of uropathogenic strains of Escherichia coli irreversibly binds to human erythrocytes (RBCs) and triggers activation of ATP release and metabolic changes ultimately leading to hemolysis. We studied the regulation of extracellular ATP (ATPe) of RBCs exposed to HlyA. Luminometry was used to assess ATP release and ATPe hydrolysis, whereas changes in cell volume and morphology were determined by electrical impedance, ektacytometry and aggregometry.

Searching for New Leads To Treat Epilepsy: Target-Based Virtual Screening for the Discovery of Anticonvulsant Agents.

The purpose of this investigation is to contribute to the development of new anticonvulsant drugs to treat patients with refractory epilepsy. We applied a virtual screening protocol that involved the search into molecular databases of new compounds and known drugs to find small molecules that interact with the open conformation of the Nav1.2 pore.

Diphenhydramine inhibits voltage-gated proton channels (Hv1) and induces acidification in leukemic Jurkat T cells- New insights into the pro-apoptotic effects of antihistaminic drugs.

An established characteristic of neoplastic cells is their metabolic reprogramming, known as the Warburg effect, with greater reliance on energetically less efficient pathways (such as glycolysis and pentose phosphate shunt) compared with oxidative phosphorylation. This results in an overproduction of acidic species that must be extruded to maintain intracellular homeostasis. We recently described that blocking the proton currents in leukemic cells mediated by Hv1 ion channels triggers a marked intracellular acidification and apoptosis induction.

Dynamic regulation of extracellular ATP in .

We studied the kinetics of extracellular ATP (ATPe) in and their outer membrane vesicles (OMVs) stimulated with amphipatic peptides melittin (MEL) and mastoparan 7 (MST7). Real-time luminometry was used to measure ATPe kinetics, ATP release, and ATPase activity. The latter was also determined by following [P]Pi released from [γ-P]ATP.

The inhibition of voltage-gated H channel (HVCN1) induces acidification of leukemic Jurkat T cells promoting cell death by apoptosis.

Cellular energetic deregulation is widely known to produce an overproduction of acidic species in cancer cells. This acid overload must be counterbalanced with a high rate of H extrusion to maintain cell viability. In this sense, many H transporters have been reported to be crucial for cell survival and proposed as antineoplastic target.

A randomized placebo-controlled lovastatin trial for neurobehavioral function in neurofibromatosis I.

Objective: Lovastatin has been shown to reverse learning deficits in a mouse model of Neurofibromatosis Type 1 (NF1), a common monogenic disorder caused by a mutation in the Ras-MAPK pathway and associated with learning disabilities. We conducted a randomized double-blind placebo-controlled trial to assess lovastatin's effects on cognition and behavior in patients with NF1.

Method: Forty-four NF1 patients (mean age 25.

Resting state functional MRI reveals abnormal network connectivity in neurofibromatosis 1.

Neurofibromatosis type I (NF1) is a genetic disorder caused by mutations in the neurofibromin 1 gene at locus 17q11.2. Individuals with NF1 have an increased incidence of learning disabilities, attention deficits, and autism spectrum disorders.

Arachidonic acid activation of BKCa (Slo1) channels associated to the β1-subunit in human vascular smooth muscle cells.

Arachidonic acid (AA) is a polyunsaturated fatty acid involved in a complex network of cell signaling. It is well known that this fatty acid can directly modulate several cellular target structures, among them, ion channels. We explored the effects of AA on high conductance Ca(2+)- and voltage-dependent K(+) channel (BKCa) in vascular smooth muscle cells (VSMCs) where the presence of β1-subunit was functionally demonstrated by lithocholic acid activation.

Autism traits in the RASopathies.

Background: Mutations in Ras/mitogen-activated protein kinase (Ras/MAPK) pathway genes lead to a class of disorders known as RASopathies, including neurofibromatosis type 1 (NF1), Noonan syndrome (NS), Costello syndrome (CS), and cardio-facio-cutaneous syndrome (CFC). Previous work has suggested potential genetic and phenotypic overlap between dysregulation of Ras/MAPK signalling and autism spectrum disorders (ASD). Although the literature offers conflicting evidence for association of NF1 and autism, there has been no systematic evaluation of autism traits in the RASopathies as a class to support a role for germline Ras/MAPK activation in ASDs.

A BK (Slo1) channel journey from molecule to physiology.

Calcium and voltage-activated potassium (BK) channels are key actors in cell physiology, both in neuronal and non-neuronal cells and tissues. Through negative feedback between intracellular Ca (2+) and membrane voltage, BK channels provide a damping mechanism for excitatory signals. Molecular modulation of these channels by alternative splicing, auxiliary subunits and post-translational modifications showed that these channels are subjected to many mechanisms that add diversity to the BK channel α subunit gene.

Human umbilical artery smooth muscle exhibits a 2-APB-sensitive capacitative contractile response evoked by vasoactive substances and expresses mRNAs for STIM, Orai and TRPC channels.

After depletion of intracellular Ca2+ stores the capacitative response triggers an extracellular Ca2+ influx through store-operated channels (SOCs) which refills these stores. Our objective was to explore if human umbilical artery smooth muscle presented this response and if it was involved in the mechanism of serotonin- and histamine-induced contractions. Intracellular Ca2+ depletion by a Ca(2+)-free extracellular solution followed by Ca2+ readdition produced a contraction in artery rings which was inhibited by the blocker of Orai and TRPC channels 2-aminoethoxydiphenyl borate (2-APB), suggesting a capacitative response.

Bupivacaine inhibits large conductance, voltage- and Ca2+- activated K+ channels in human umbilical artery smooth muscle cells.

Bupivacaine is a local anesthetic compound belonging to the amino amide group. Its anesthetic effect is commonly related to its inhibitory effect on voltage-gated sodium channels. However, several studies have shown that this drug can also inhibit voltage-operated K(+) channels by a different blocking mechanism.

Extracellular ATP induces fast and transient non-selective cationic currents and cytosolic Ca2+ changes in human umbilical artery smooth muscle cells.

Ionotropic purinergic receptors (P2X) are expressed in endothelial and smooth muscle cells of blood vessels. ATP acting on smooth muscle P2X receptors is able to induce vasoconstriction in different kind of vessels. However, to our knowledge, there are no reports that directly show the activity of these purinergic receptors in native human vascular smooth muscle cells.

Risperidone inhibits contractions induced by serotonin and histamine and reduces K+ currents in smooth muscle of human umbilical artery.

Risperidone is an antipsychotic commonly used during pregnancy. Because it can cross the placental barrier, our objective was to evaluate its actions on the smooth muscle of the human umbilical artery (HUA). Risperidone preincubation (1-300 nmol/L for 20 minutes) produced a significant decrease in maximum force development induced by serotonin or histamine in HUA rings.

Arginine-rich peptides destabilize the plasma membrane, consistent with a pore formation translocation mechanism of cell-penetrating peptides.

Recent molecular-dynamics simulations have suggested that the arginine-rich HIV Tat peptides translocate by destabilizing and inducing transient pores in phospholipid bilayers. In this pathway for peptide translocation, Arg residues play a fundamental role not only in the binding of the peptide to the surface of the membrane, but also in the destabilization and nucleation of transient pores across the bilayer. Here we present a molecular-dynamics simulation of a peptide composed of nine Args (Arg-9) that shows that this peptide follows the same translocation pathway previously found for the Tat peptide.