scholarly journals Phenylalanine-Derived β-Lactam TRPM8 Modulators. Configuration Effect on the Antagonist Activity

2021 ◽  
Vol 22 (5) ◽  
pp. 2370
Author(s):  
María Ángeles Bonache ◽  
Pedro Juan Llabrés ◽  
Cristina Martín-Escura ◽  
Roberto De la Torre-Martínez ◽  
Alicia Medina-Peris ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Neuronal Excitability ◽  
Primary Cultures ◽  
Receptor Potential ◽  
High Specificity ◽  
Docking Studies ◽  
Antagonist Activity ◽  
Patch Clamp Electrophysiology ◽  
Transient Receptor ◽  
Highly Hydrophobic

Transient receptor potential cation channel subfamily M member 8 (TRPM8) is a Ca2+ non-selective ion channel implicated in a variety of pathological conditions, including cancer, inflammatory and neuropathic pain. In previous works we identified a family of chiral, highly hydrophobic β–lactam derivatives, and began to intuit a possible effect of the stereogenic centers on the antagonist activity. To investigate the influence of configuration on the TRPM8 antagonist properties, here we prepare and characterize four possible diastereoisomeric derivatives of 4-benzyl-1-[(3’-phenyl-2’-dibenzylamino)prop-1’-yl]-4-benzyloxycarbonyl-3-methyl-2-oxoazetidine. In microfluorography assays, all isomers were able to reduce the menthol-induced cell Ca2+ entry to larger or lesser extent. Potency follows the order 3R,4R,2’R > 3S,4S,2’R ≅ 3R,4R,2’S > 3S,4S,2’S, with the most potent diastereoisomer showing a half inhibitory concentration (IC50) in the low nanomolar range, confirmed by Patch-Clamp electrophysiology experiments. All four compounds display high receptor selectivity against other members of the TRP family. Furthermore, in primary cultures of rat dorsal root ganglion (DRG) neurons, the most potent diastereoisomers do not produce any alteration in neuronal excitability, indicating their high specificity for TRPM8 channels. Docking studies positioned these β-lactams at different subsites by the pore zone, suggesting a different mechanism than the known N-(3-aminopropyl)-2-[(3-methylphenyl)methoxy]-N-(2-thienylmethyl)-benzamide (AMTB) antagonist.

scholarly journals A capsaicinoid-based soft drug, AG1529, for attenuating TRPV1-mediated histaminergic and inflammatory sensory neuron excitability

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Magdalena Nikolaeva-Koleva ◽  
Laura Butron ◽  
Sara González-Rodríguez ◽  
Isabel Devesa ◽  
Pierluigi Valente ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Primary Cultures ◽  
Receptor Potential ◽  
Neuronal Firing ◽  
In Vivo Model ◽  
Drg Neurons ◽  
Trpv1 Channels ◽  
Soft Drug ◽  
Transient Receptor

AbstractTRPV1, a member of the transient receptor potential (TRP) family, is a nonselective calcium permeable ion channel gated by physical and chemical stimuli. In the skin, TRPV1 plays an important role in neurogenic inflammation, pain and pruritus associated to many dermatological diseases. Consequently, TRPV1 modulators could represent pharmacological tools to respond to important patient needs that still represent an unmet medical demand. Previously, we reported the design of capsaicinoid-based molecules that undergo dermal deactivation (soft drugs), thus preventing their long-term dermal accumulation. Here, we investigated the pharmacological properties of the lead antagonist, 2-((4-hydroxy-2-iodo-5-methoxybenzyl) amino)-2-oxoethyl dodecanoate (AG1529), on heterologously expressed human TRPV1 (hTRPV1), on nociceptor excitability and on an in vivo model of acute pruritus. We report that AG1529 competitively blocked capsaicin-evoked activation of hTRPV1 with micromolar potency, moderately affected pH-induced gating, and did not alter voltage- and heat-mediated responses. AG1529 displays modest receptor selectivity as it mildly blocked recombinant hTRPA1 and hTRPM8 channels. In primary cultures of rat dorsal root ganglion (DRG) neurons, AG1529 potently reduced capsaicin-evoked neuronal firing. AG1529 exhibited lower potency on pH-evoked TRPV1 firing, and TRPA1-elicited nociceptor excitability. Furthermore, AG1529 abolished histaminergic and inflammation mediated TRPV1 sensitization in primary cultures of DRG neurons. Noteworthy, dermal wiping of AG1529, either in an acetone-based formulation or in an anhydrous ointment, dose-dependently attenuated acute histaminergic itch in a rodent model. This cutaneous anti-pruritic effect was devoid of the normal nocifensive action evoked by the burning sensation of capsaicin. Taken together, these preclinical results unveil the mode of action of AG1529 on TRPV1 channels and substantiate the tenet that this capsaicinoid-based soft drug is a promising candidate for drug development as a topical anti-pruritic and anti-inflammatory medication.

Nifedipine-activated Ca2+ permeability in newborn rat cortical collecting duct cells in primary culture

2001 ◽  
Vol 280 (5) ◽  
pp. C1193-C1203 ◽  
Author(s):  
Laura Valencia ◽  
Michel Bidet ◽  
Sonia Martial ◽  
Elsa Sanchez ◽  
Estela Melendez ◽  
...  
Keyword(s):  
Primary Culture ◽  
Transient Receptor Potential ◽  
Collecting Duct ◽  
Primary Cultures ◽  
Receptor Potential ◽  
Cortical Collecting Duct ◽  
Newborn Rat ◽  
Adult Rat ◽  
Intracellular Ca ◽  
Transient Receptor

To characterize Ca2+ transport in newborn rat cortical collecting duct (CCD) cells, we used nifedipine, which in adult rat distal tubules inhibits the intracellular Ca2+concentration ([Ca2+]i) increase in response to hormonal activation. We found that the dihydropyridine (DHP) nifedipine (20 μM) produced an increase in [Ca2+]i from 87.6 ± 3.3 nM to 389.9 ± 29.0 nM in 65% of the cells. Similar effects of other DHP (BAY K 8644, isradipine) were also observed. Conversely, DHPs did not induce any increase in [Ca2+]i in cells obtained from proximal convoluted tubule. In CCD cells, neither verapamil nor diltiazem induced any rise in [Ca2+]i. Experiments in the presence of EGTA showed that external Ca2+ was required for the nifedipine effect, while lanthanum (20 μM), gadolinium (100 μM), and diltiazem (20 μM) inhibited the effect. Experiments done in the presence of valinomycin resulted in the same nifedipine effect, showing that K+ channels were not involved in the nifedipine-induced [Ca2+]i rise. H2O2also triggered [Ca2+]i rise. However, nifedipine-induced [Ca2+]i increase was not affected by protamine. In conclusion, the present results indicate that 1) primary cultures of cells from terminal nephron of newborn rats are a useful tool for investigating Ca2+transport mechanisms during growth, and 2) newborn rat CCD cells in primary culture exhibit a new apical nifedipine-activated Ca2+ channel of capacitive type (either transient receptor potential or leak channel).

scholarly journals Targeted millisecond-scale activation of cells using non-invasive Sonogenetics

2020 ◽  
Author(s):  
Marc Duque ◽  
Corinne A. Lee-Kubli ◽  
Yusuf Tufail ◽  
Uri Magaram ◽  
Jose Mendoza Lopez ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Transient Receptor Potential ◽  
Neuronal Excitability ◽  
Receptor Potential ◽  
Cell Types ◽  
Mammalian Brain ◽  
Non Invasive ◽  
Transient Receptor Potential A1 ◽  
Layer V ◽  
Transient Receptor

Our understanding of the nervous system has been fundamentally advanced by light- and small molecule-sensitive proteins that can be used to modify neuronal excitability. However, optogenetics requires invasive instrumentation while chemogenetics lacks temporal control. Here, we identify a candidate channel that confers sensitivity to non-invasive ultrasound on millisecond timescales. Using a functional screen, we find that human Transient Receptor Potential A1 (hsTRPA1) increases ultrasound-evoked intracellular calcium levels and membrane potentials. Ultrasound, but not agonist, -evoked, gating of hsTRPA1, requires the N-terminal tip region, intact actin cytoskeleton, and cholesterol, implicating these features in the sonogenetic mechanism. We then use calcium imaging and electrophysiology to confirm that ultrasound-evoked responses of primary neurons are potentiated by hsTRPA1. We also show that unilateral expression of hsTRPA1 in mouse layer V motor cortical neurons leads to ultrasound-evoked contralateral limb responses to ultrasound delivered through an intact skull. Finally, ultrasound induces c-fos in hsTRPA1-expressing neurons, suggesting that our approach can be used for targeted activation of neural circuits. Together, our results demonstrate that hsTRPA1-based sonogenetics can effectively and non-invasively modulate neurons within the intact mammalian brain, a method that could be extended to other cell types across species.

scholarly journals Transient Receptor Potential Ankyrin-1 (TRPA1) Block Protects against Loss of White Matter Function during Ischaemia in the Mouse Optic Nerve

2021 ◽  
Vol 14 (9) ◽  
pp. 909
Author(s):  
Wendy Lajoso ◽  
Grace Flower ◽  
Vincenzo Giacco ◽  
Anjuli Kaul ◽  
Circe La Mache ◽  
...  
Keyword(s):  
White Matter ◽  
Optic Nerve ◽  
Transient Receptor Potential ◽  
Neuronal Excitability ◽  
Receptor Potential ◽  
Glucose Deprivation ◽  
Compound Action Potential ◽  
Oxygen And Glucose Deprivation ◽  
Neuronal Transmission ◽  
Transient Receptor

Oligodendrocytes produce myelin, which provides insulation to axons and speeds up neuronal transmission. In ischaemic conditions, myelin is damaged, resulting in mental and physical disabilities. Recent evidence suggests that oligodendrocyte damage during ischaemia can be mediated by Transient Receptor Potential Ankyrin-1 (TRPA1), whose activation raises intracellular Ca2+ concentrations and damages compact myelin. Here, we show that TRPA1 is constitutively active in oligodendrocytes and the optic nerve, as the specific TRPA1 antagonist, A-967079, decreases basal oligodendrocyte Ca2+ concentrations and increases the size of the compound action potential (CAP). Conversely, TRPA1 agonists reduce the size of the optic nerve CAP in an A-967079-sensitive manner. These results indicate that glial TRPA1 regulates neuronal excitability in the white matter under physiological as well as pathological conditions. Importantly, we find that inhibition of TRPA1 prevents loss of CAPs during oxygen and glucose deprivation (OGD) and improves the recovery. TRPA1 block was effective when applied before, during, or after OGD, indicating that the TRPA1-mediated damage is occurring during both ischaemia and recovery, but importantly, that therapeutic intervention is possible after the ischaemic insult. These results indicate that TRPA1 has an important role in the brain, and that its block may be effective in treating many white matter diseases.

TRPC3 mediates hyperexcitability and epileptiform activity in immature cortex and experimental cortical dysplasia

2014 ◽  
Vol 111 (6) ◽  
pp. 1227-1237 ◽  
Author(s):  
Fu-Wen Zhou ◽  
Steven N. Roper
Keyword(s):  
Transient Receptor Potential ◽  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Epileptiform Activity ◽  
Receptor Potential ◽  
Synaptic Activity ◽  
Bath Application ◽  
Enhanced Expression ◽  
Transient Receptor ◽  
Canonical Type

Neuronal hyperexcitability plays an important role in epileptogenesis. Conditions of low extracellular calcium (Ca) or magnesium (Mg) can induce hyperexcitability and epileptiform activity with unclear mechanisms. Transient receptor potential canonical type 3 (TRPC3) channels play a pivotal role in neuronal excitability and are activated in low-Ca and/or low-Mg conditions to depolarize neurons. TRPC3 staining was highly enriched in immature, but very weak in mature, control cortex, whereas it was strong in dysplastic cortex at all ages. Depolarization and susceptibility to epileptiform activity increased with decreasing Ca and Mg. Combinations of low Ca and low Mg induced larger depolarization in pyramidal neurons and greater susceptibility to epileptiform activity in immature and dysplastic cortex than in mature and control cortex, respectively. Intracellular application of anti-TRPC3 antibody to block TRPC3 channels and bath application of the selective TRPC3 inhibitor Pyr3 greatly diminished depolarization in immature control and both immature and mature dysplastic cortex with strong TRPC3 expression. Epileptiform activity was initiated in low Ca and low Mg when synaptic activity was blocked, and Pyr3 completely suppressed this activity. In conclusion, TRPC3 primarily mediates low Ca- and low Mg-induced depolarization and epileptiform activity, and the enhanced expression of TRPC3 could make dysplastic and immature cortex more hyperexcitable and more susceptible to epileptiform activity.

scholarly journals Expression of store-operated Ca2+ entry and transient receptor potential canonical and vanilloid-related proteins in rat distal pulmonary venous smooth muscle

2010 ◽  
Vol 299 (5) ◽  
pp. L621-L630 ◽  
Author(s):  
Gongyong Peng ◽  
Wenju Lu ◽  
Xiaoyan Li ◽  
Yuqin Chen ◽  
Nanshan Zhong ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Transient Receptor Potential ◽  
Pulmonary Veins ◽  
Primary Cultures ◽  
Pulmonary Arteries ◽  
Receptor Potential ◽  
Hypoxic Pulmonary Hypertension ◽  
Fura 2 ◽  
Transient Receptor

Chronic hypoxia causes remodeling and alters contractile responses in both pulmonary arteries and pulmonary veins. Although pulmonary arteries have been studied extensively in these disorders, the mechanisms by which pulmonary veins respond to hypoxia and whether these responses contribute to chronic hypoxic pulmonary hypertension remain poorly understood. In pulmonary arterial smooth muscle, we have previously demonstrated that influx of Ca2+ through store-operated calcium channels (SOCC) thought to be composed of transient receptor potential (TRP) proteins is likely to play an important role in development of chronic hypoxic pulmonary hypertension. To determine whether this mechanism could also be operative in pulmonary venous smooth muscle, we measured intracellular Ca2+ concentration ([Ca2+]i) by fura-2 fluorescence microscopy in primary cultures of pulmonary venous smooth muscle cells (PVSMC) isolated from rat distal pulmonary veins. In cells perfused with Ca2+-free media containing cyclopiazonic acid (10 μM) and nifedipine (5 μM) to deplete sarcoplasmic reticulum Ca2+ stores and block voltage-dependent Ca2+ channels, restoration of extracellular Ca2+ (2.5 mM) caused marked increases in [Ca2+]i, whereas MnCl2 (200 μM) quenched fura-2 fluorescence, indicating store-operated Ca2+ entry (SOCE). SKF-96365 and NiCl2, antagonists of SOCC, blocked SOCE at concentrations that did not alter Ca2+ responses to 60 mM KCl. Of the seven known canonical TRP (TRPC1–7) and six vanilloid-related TRP channels (TRPV1–6), real-time PCR revealed mRNA expression of TRPC1 > TRPC6 > TRPC4 > TRPC2 ≈ TRPC5 > TRPC3, TRPV2 > TRPV4 > TRPV1 in distal PVSMC, and TRPC1 > TRPC6 > TRPC3 > TRPC4 ≈ TRPC5, TRPV2 ≈ TRPV4 > TRPV1 in rat distal pulmonary vein (PV) smooth muscle. Western blotting confirmed protein expression of TRPC1, TRPC6, TRPV2, and TRPV4 in both PVSMC and PV. Our results suggest that SOCE through Ca2+ channels composed of TRP proteins may contribute to Ca2+ signaling in rat distal PV smooth muscle.

scholarly journals Using the Patch-Clamp technique to shed light on ion channels structure, function and pharmacology

2014 ◽  
Author(s):  
Roberta Gualdani
Keyword(s):  
Ion Channels ◽  
Patch Clamp ◽  
Transient Receptor Potential ◽  
Neuronal Excitability ◽  
Receptor Potential ◽  
Cellular Membrane ◽  
Bk Channel ◽  
K Channel ◽  
Patch Clamp Technique ◽  
Transient Receptor

Ion channels are membrane proteins that selectively allow ions to flow down their electrochemical gradient across the cellular membrane. They localize in both plasma and intracellular membranes and regulate a variety of functions such as neuronal excitability, heartbeat, muscle contraction and hormones release. Thus, understanding the molecular mechanism of ion channels function and regulation is one of the key goals of modern Biophysics. During my PhD thesis, by combining patch-clamp measurements with site-direct mutagenesis, fluorophore labeling experiments and pharmacological assays, I explored some functional and structural properties of different ion transporters: the Na+/Ca2+ exchanger (NCX); the large conductance Ca2+-voltage activated K+ channel (BK) channel; the human Transient receptor potential, member A1 (TRPA1) channel.

scholarly journals Cocaine self-administration in mice with forebrain knock-down of trpc5 ion channels

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 53 ◽  
Author(s):  
Matthew B Pomrenze ◽  
Michael V Baratta ◽  
Kristin C Rasmus ◽  
Brian A Cadle ◽  
Shinya Nakamura ◽  
...  
Keyword(s):  
Dose Response ◽  
Transient Receptor Potential ◽  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Receptor Potential ◽  
Trpc Channels ◽  
Self Administration ◽  
Data Set ◽  
Knock Down ◽  
Transient Receptor

Canonical transient receptor potential (TRPC) channels are a family of non-selective cation channels that play a crucial role in modulating neuronal excitability due to their involvement in intracellular Ca2+ regulation and dendritic growth. TRPC5 channels a) are one of the two most prevalent TRPC channels in the adult rodent brain; b) are densely expressed in deep layer pyramidal neurons of the prefrontal cortex (PFC); and c) modulate neuronal persistent activity necessary for working memory and attention. In order to evaluate the causal role of TRPC5 in motivation/reward-related behaviors, conditional forebrain TRPC5 knock-down (trpc5-KD) mice were generated and trained to nose-poke for intravenous cocaine. Here we present a data set containing the first 6 days of saline or cocaine self-administration in wild type (WT) and trpc5-KD mice. In addition, we also present a data set showing the dose-response to cocaine after both groups had achieved similar levels of cocaine self-administration. Compared to WT mice, trpc5-KD mice exhibited an apparent increase in self-administration on the first day of cocaine testing without prior operant training. There were no apparent differences between WT and trpc5-KD mice for saline responding on the first day of training. Both groups showed similar dose-response sensitivity to cocaine after several days of achieving similar levels of cocaine intake.

scholarly journals Effect of transient receptor potential vanilloid 4 activation on the delayed rectifier potassium current in the hippocampal pyramidal neurons and Kv subunit expression in the hippocampi of mice

2020 ◽  
Author(s):  
Li Zhou ◽  
Weixing Xu ◽  
Dong An ◽  
Chen Men ◽  
Yingchun Li ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Receptor Potential ◽  
Delayed Rectifier ◽  
Transient Receptor Potential Vanilloid ◽  
Hippocampal Pyramidal Neurons ◽  
Protein Levels ◽  
Voltage Dependent ◽  
Transient Receptor

Abstract Activation of transient receptor potential vanilloid 4 (TRPV4) can increase hippocampal neuronal excitability. Recent studies have reported that TRPV4 may be involved in the pathogenesis of epilepsy. Voltage-gated potassium channels (VGPCs) play an important role in regulating neuronal excitability and abnormal VGPCs expression or function is related to epilepsy. Activation of TRPV4 can modulate ion channels, but whether activation of it could modulate VGPCs in hippocampal neurons remains unknown. Here we examined the effect of TRPV4 activation on the delayed rectifier potassium current (IK) in the hippocampal pyramidal neurons and on the Kv subunits expression. We also explored the role of TRPV4 in changes in Kv subunits expression in mice following pilocarpine-induced status epilepticus (PISE). Application of TRPV4 agonists, GSK1016790A and 5,6-EET, markedly reduced IK in the hippocampal pyramidal neurons, shifted the voltage-dependent inactivation curve to the hyperpolarization direction, and had no effect on the voltage-dependent activation curve. GSK1016790A- and 5,6-EET-induced inhibition of IK was blocked by TRPV4 specific antagonists, HC-067047 and RN1734. GSK1016790A-induced inhibition of IK was markedly attenuated by calcium/calmodulin-dependent kinase II (CaMKII) antagonist, but was not affected by protein kinase C or protein kinase A antagonists. Application of GSK1016790A for up to 1 h did not change the hippocampal protein levels of Kv1.1, Kv1.2, or Kv2.1. Intracerebroventricular injection of GSK1016790A for 3 d reduced the hippocampal protein levels of Kv1.2 and Kv2.1, leaving that of Kv1.1 unchanged. Kv1.2 and Kv2.1 protein levels were reduced markedly in hippocampi on day 3 post PISE, which was significantly reversed by HC-067047. We conclude that activation of TRPV4 inhibits IK in the hippocampal pyramidal neurons, possibly by activating CaMKII. Persistent activation of TRPV4 decreased Kv1.2 and Kv2.1 expression, which may be associated with the decrease in Kv1.2 and Kv2.1 expression following PISE.

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