scholarly journals Properties of the Inner Pore Region of TRPV1 Channels Revealed by Block with Quaternary Ammoniums

2008 ◽  
Vol 132 (5) ◽  
pp. 547-562 ◽  
Author(s):  
Andrés Jara-Oseguera ◽  
Itzel Llorente ◽  
Tamara Rosenbaum ◽  
León D. Islas
Keyword(s):  
Transient Receptor Potential ◽  
Structural Information ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Dependent Manner ◽  
Trpv1 Channels ◽  
Quaternary Ammonium Ions ◽  
Activation Gate ◽  
Transient Receptor ◽  
Inner Pore

The transient receptor potential vanilloid 1 (TRPV1) nonselective cationic channel is a polymodal receptor that activates in response to a wide variety of stimuli. To date, little structural information about this channel is available. Here, we used quaternary ammonium ions (QAs) of different sizes in an effort to gain some insight into the nature and dimensions of the pore of TRPV1. We found that all four QAs used, tetraethylammonium (TEA), tetrapropylammonium (TPrA), tetrabutylammonium, and tetrapentylammonium, block the TRPV1 channel from the intracellular face of the channel in a voltage-dependent manner, and that block by these molecules occurs with different kinetics, with the bigger molecules becoming slower blockers. We also found that TPrA and the larger QAs can only block the channel in the open state, and that they interfere with the channel's activation gate upon closing, which is observed as a slowing of tail current kinetics. TEA does not interfere with the activation gate, indicating that this molecule can reside in its blocking site even when the channel is closed. The dependence of the rate constants on the size of the blocker suggests a size of around 10 Å for the inner pore of TRPV1 channels.

scholarly journals Interactions between Chemesthesis and Taste: Role of TRPA1 and TRPV1

2021 ◽  
Vol 22 (7) ◽  
pp. 3360
Author(s):  
Mee-Ra Rhyu ◽  
Yiseul Kim ◽  
Vijay Lyall
Keyword(s):  
Transient Receptor Potential ◽  
Taste Receptor ◽  
Sensory Nerve ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Trpv1 Channels ◽  
Trigeminal Neurons ◽  
Calcitonin Gene ◽  
Transient Receptor

In addition to the sense of taste and olfaction, chemesthesis, the sensation of irritation, pungency, cooling, warmth, or burning elicited by spices and herbs, plays a central role in food consumption. Many plant-derived molecules demonstrate their chemesthetic properties via the opening of transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) channels. TRPA1 and TRPV1 are structurally related thermosensitive cation channels and are often co-expressed in sensory nerve endings. TRPA1 and TRPV1 can also indirectly influence some, but not all, primary taste qualities via the release of substance P and calcitonin gene-related peptide (CGRP) from trigeminal neurons and their subsequent effects on CGRP receptor expressed in Type III taste receptor cells. Here, we will review the effect of some chemesthetic agonists of TRPA1 and TRPV1 and their influence on bitter, sour, and salt taste qualities.

scholarly journals Computational Modeling to Explain Why 5,5-Diarylpentadienamides are TRPV1 Antagonists

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1765
Author(s):  
Julio Caballero
Keyword(s):  
Transient Receptor Potential ◽  
Structural Information ◽  
Chemical Activation ◽  
Receptor Potential ◽  
Quantitative Structure Activity Relationship ◽  
Structural Features ◽  
Transient Receptor Potential Vanilloid ◽  
Protein Residues ◽  
Topological Features ◽  
Transient Receptor

Several years ago, the crystallographic structures of the transient receptor potential vanilloid 1 (TRPV1) in the presence of agonists and antagonists were reported, providing structural information about its chemical activation and inactivation. TRPV1’s activation increases the transport of calcium and sodium ions, leading to the excitation of sensory neurons and the perception of pain. On the other hand, its antagonistic inactivation has been explored to design analgesic drugs. The interactions between the antagonists 5,5-diarylpentadienamides (DPDAs) and TRPV1 were studied here to explain why they inactivate TRPV1. The present work identified the structural features of TRPV1–DPDA complexes, starting with a consideration of the orientations of the ligands inside the TRPV1 binding site by using molecular docking. After this, a chemometrics analysis was performed (i) to compare the orientations of the antagonists (by using LigRMSD), (ii) to describe the recurrent interactions between the protein residues and ligand groups in the complexes (by using interaction fingerprints), and (iii) to describe the relationship between topological features of the ligands and their differential antagonistic activities (by using a quantitative structure–activity relationship (QSAR) with 2D autocorrelation descriptors). The interactions between the DPDA groups and the residues Y511, S512, T550, R557, and E570 (with a recognized role in the binding of classic ligands), and the occupancy of isoquinoline or 3-hydroxy-3,4-dihydroquinolin-2(1H)-one groups of the DPDAs in the vanilloid pocket of TRPV1 were clearly described. Based on the results, the structural features that explain why DPDAs inactivate TRPV1 were clearly exposed. These features can be considered for the design of novel TRPV1 antagonists.

scholarly journals TRPV1 channels and the progesterone receptor Sig-1R interact to regulate pain

2018 ◽  
Vol 115 (7) ◽  
pp. E1657-E1666 ◽  
Author(s):  
Miguel Ortíz-Rentería ◽  
Rebeca Juárez-Contreras ◽  
Ricardo González-Ramírez ◽  
León D. Islas ◽  
Félix Sierra-Ramírez ◽  
...  
Keyword(s):  
Transient Receptor Potential ◽  
Trp Channels ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Sigma 1 Receptor ◽  
Trpv1 Channels ◽  
Nociceptive Responses ◽  
Sigma 1 ◽  
Transient Receptor ◽  
Thermal Stimuli

The Transient Receptor Potential Vanilloid 1 (TRPV1) ion channel is expressed in nociceptors where, when activated by chemical or thermal stimuli, it functions as an important transducer of painful and itch-related stimuli. Although the interaction of TRPV1 with proteins that regulate its function has been previously explored, their modulation by chaperones has not been elucidated, as is the case for other mammalian TRP channels. Here we show that TRPV1 physically interacts with the Sigma 1 Receptor (Sig-1R), a chaperone that binds progesterone, an antagonist of Sig-1R and an important neurosteroid associated to the modulation of pain. Antagonism of Sig-1R by progesterone results in the down-regulation of TRPV1 expression in the plasma membrane of sensory neurons and, consequently, a decrease in capsaicin-induced nociceptive responses. This is observed both in males treated with a synthetic antagonist of Sig-1R and in pregnant females where progesterone levels are elevated. This constitutes a previously undescribed mechanism by which TRPV1-dependent nociception and pain can be regulated.

scholarly journals Activation of TRPV1 channels leads to stimulation of NKCC1 cotransport in the lens

2018 ◽  
Vol 315 (6) ◽  
pp. C793-C802 ◽  
Author(s):  
Mohammad Shahidullah ◽  
Amritlal Mandal ◽  
Nicholas A. Delamere
Keyword(s):  
Ion Transport ◽  
Transient Receptor Potential ◽  
Ion Homeostasis ◽  
Receptor Potential ◽  
Transient Receptor Potential Vanilloid ◽  
Signaling Mechanism ◽  
Trpv1 Channels ◽  
Trpv1 Antagonist ◽  
Transient Receptor ◽  
Stimulation Of

Lens ion homeostasis is crucial in maintaining water content and, in turn, refractive index and transparency of the multicellular syncytium-like structure. New information is emerging on the regulation of ion transport in the lens by mechanisms that rely on transient receptor potential vanilloid (TRPV) ion channels. We found recently that TRPV1 activation leads to Ca2+/PKC-dependent ERK1/2 signaling. Here, we show that the TRPV1 agonist capsaicin (100 nM) and hyperosmotic solution (350 vs. 300 mosM) each caused an increase of bumetanide-inhibitable Rb uptake by intact porcine lenses and Na-K-2Cl cotransporter 1 (NKCC1) phosphorylation in the lens epithelium. The TRPV1 antagonist A889425 (1 µM) abolished the increases of Rb uptake and NKCC1 phosphorylation in response to hyperosmotic solution. Exposing lenses to hyperosmotic solution in the presence of MEK/ERK inhibitor U0126 (10 µM) or the with-no-lysine kinase (WNK) inhibitor WNK463 (1 µM) also prevented NKCC1 phosphorylation and the Rb uptake responses to hyperosmotic solution. WNK463 did not prevent the increase in ERK1/2 phosphorylation that occurs in response to capsaicin or hyperosmotic solution, suggesting that ERK1/2 activation occurs before WNK activation in the sequence of signaling events. Taken together, the evidence indicates that activation of TRPV1 is a critical early step in a signaling mechanism that responds to a hyperosmotic stimulus, possibly lens shrinkage. By activating ERK1/2 and WNK, TRPV1 activation leads to NKCC1 phosphorylation and stimulation of NKCC1-mediated ion transport.

scholarly journals Pore Helix Domain Is Critical to Camphor Sensitivity of Transient Receptor Potential Vanilloid 1 Channel

2012 ◽  
Vol 116 (4) ◽  
pp. 903-917 ◽  
Author(s):  
Lenka Marsakova ◽  
Filip Touska ◽  
Jan Krusek ◽  
Viktorie Vlachova
Keyword(s):  
Spatial Distribution ◽  
Plasma Membranes ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Structural Basis ◽  
Transient Receptor Potential Vanilloid ◽  
Trpv1 Channel ◽  
Patch Clamp Technique ◽  
Trpv1 Channels ◽  
Transient Receptor

Background The recent discovery that camphor activates and strongly desensitizes the capsaicin-sensitive and noxious heat-sensitive channel transient receptor potential vanilloid subfamily member 1 (TRPV1) has provided new insights and opened up new research paths toward understanding why this naturally occurring monoterpene is widely used in human medicine for its local counter-irritant, antipruritic, and anesthetic properties. However, the molecular basis for camphor sensitivity remains mostly unknown. The authors attempt to explore the nature of the activation pathways evoked by camphor and narrow down a putative interaction site at TRPV1. Methods The authors transiently expressed wild-type or specifically mutated recombinant TRPV1 channels in human embryonic kidney cells HEK293T and recorded cation currents with the whole cell, patch clamp technique. To monitor changes in the spatial distribution of phosphatidylinositol 4,5-bisphosphate, they used fluorescence resonance energy transfer measurements from cells transfected with the fluorescent protein-tagged pleckstrin homology domains of phospholipase C. Results The results revealed that camphor modulates TRPV1 channel through the outer pore helix domain by affecting its overall gating equilibrium. In addition, camphor, which generally is known to decrease the fluidity of cell plasma membranes, may also regulate the activity of TRPV1 by inducing changes in the spatial distribution of phosphatidylinositol-4,5-bisphosphate on the inner leaflet of the plasma membrane. Conclusions The findings of this study provide novel insights into the structural basis for the modulation of TRPV1 channel by camphor and may provide an explanation for the mechanism by which camphor modulates thermal sensation in vivo.

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