scholarly journals Electrophysiological and Molecular Mechanisms of Sinoatrial Node Mechanosensitivity

2021 ◽  
Vol 8 ◽  
Author(s):  
Daniel Turner ◽  
Chen Kang ◽  
Pietro Mesirca ◽  
Juan Hong ◽  
Matteo E. Mangoni ◽  
...  

The understanding of the electrophysiological mechanisms that underlie mechanosensitivity of the sinoatrial node (SAN), the primary pacemaker of the heart, has been evolving over the past century. The heart is constantly exposed to a dynamic mechanical environment; as such, the SAN has numerous canonical and emerging mechanosensitive ion channels and signaling pathways that govern its ability to respond to both fast (within second or on beat-to-beat manner) and slow (minutes) timescales. This review summarizes the effects of mechanical loading on the SAN activity and reviews putative candidates, including fast mechanoactivated channels (Piezo, TREK, and BK) and slow mechanoresponsive ion channels [including volume-regulated chloride channels and transient receptor potential (TRP)], as well as the components of mechanochemical signal transduction, which may contribute to SAN mechanosensitivity. Furthermore, we examine the structural foundation for both mechano-electrical and mechanochemical signal transduction and discuss the role of specialized membrane nanodomains, namely, caveolae, in mechanical regulation of both membrane and calcium clock components of the so-called coupled-clock pacemaker system responsible for SAN automaticity. Finally, we emphasize how these mechanically activated changes contribute to the pathophysiology of SAN dysfunction and discuss controversial areas necessitating future investigations. Though the exact mechanisms of SAN mechanosensitivity are currently unknown, identification of such components, their impact into SAN pacemaking, and pathological remodeling may provide new therapeutic targets for the treatment of SAN dysfunction and associated rhythm abnormalities.

2007 ◽  
Vol 292 (1) ◽  
pp. R64-R76 ◽  
Author(s):  
Michael J. Caterina

Living organisms must evaluate changes in environmental and internal temperatures to mount appropriate physiological and behavioral responses conducive to survival. Classical physiology has provided a wealth of information regarding the specialization of thermosensory functions among subclasses of peripheral sensory neurons and intrinsically thermosensitive neurons within the hypothalamus. However, until recently, the molecular mechanisms by which these cells carry out thermometry have remained poorly understood. The demonstration that certain ion channels of the transient receptor potential (TRP) family can be activated by increases or decreases in ambient temperature, along with the recognition of their heterogeneous expression patterns and heterogeneous temperature sensitivities, has led investigators to evaluate these proteins as candidate endogenous thermosensors. Much of this work has involved one specific channel, TRP vanilloid 1 (TRPV1), which is both a receptor for capsaicin and related pungent vanilloid compounds and a “heat receptor,” capable of directly depolarizing neurons in response to temperatures >42°C. Evidence for a contribution of TRPV1 to peripheral thermosensation has come from pharmacological, physiological, and genetic approaches. In contrast, although capsaicin-sensitive mechanisms clearly influence core body temperature regulation, the specific contribution of TRPV1 to this process remains a matter of debate. Besides TRPV1, at least six additional thermally sensitive TRP channels have been identified in mammals, and many of these also appear to participate in thermosensation. Moreover, the identification of invertebrate TRP channels, whose genetic ablation alters thermally driven behaviors, makes it clear that thermosensation represents an evolutionarily conserved role of this ion channel family.


2018 ◽  
Vol 120 (3) ◽  
pp. 1198-1211 ◽  
Author(s):  
Ileana Hernández-Araiza ◽  
Sara L. Morales-Lázaro ◽  
Jesús Aldair Canul-Sánchez ◽  
León D. Islas ◽  
Tamara Rosenbaum

Lysophosphatidic acid (LPA) is a bioactive phospholipid that exhibits a wide array of functions that include regulation of protein synthesis and adequate development of organisms. LPA is present in the membranes of cells and in the serum of several mammals and has also been shown to participate importantly in pathophysiological conditions. For several decades it was known that LPA produces some of its effects in cells through its interaction with specific G protein-coupled receptors, which in turn are responsible for signaling pathways that regulate cellular function. Among the target proteins for LPA receptors are ion channels that modulate diverse aspects of the physiology of cells and organs where they are expressed. However, recent studies have begun to unveil direct effects of LPA on ion channels, highlighting this phospholipid as a direct agonist and adding to the knowledge of the field of lipid-protein interactions. Moreover, the roles of LPA in pathophysiological conditions associated with the function of some ion channels have also begun to be clarified, and molecular mechanisms have been identified. This review focuses on the effects of LPA on ion channel function under normal and pathological conditions and highlights our present knowledge of the mechanisms by which it regulates the function and expression of N- and T-type Ca++ channels; M-type K+ channel and inward rectifier K+ channel subunit 2.1; transient receptor potential (TRP) melastatin 2, TRP vanilloid 1, and TRP ankyrin 1 channels; and TWIK-related K+ channel 1 (TREK-1), TREK-2, TWIK-related spinal cord K+ channel (TRESK), and TWIK-related arachidonic acid-stimulated K+ channel (TRAAK).


2010 ◽  
Vol 112 (3) ◽  
pp. 729-741 ◽  
Author(s):  
John P. M. White ◽  
Mario Cibelli ◽  
Antonio Rei Fidalgo ◽  
Cleoper C. Paule ◽  
Faruq Noormohamed ◽  
...  

Pain originating in inflammation is the most common pathologic pain condition encountered by the anesthesiologist whether in the context of surgery, its aftermath, or in the practice of pain medicine. Inflammatory agents, released as components of the body's response to peripheral tissue damage or disease, are now known to be collectively capable of activating transient receptor potential vanilloid type 1, transient receptor potential vanilloid type 4, transient receptor potential ankyrin type 1, and acid-sensing ion channels, whereas individual agents may activate only certain of these ion channels. These ionotropic receptors serve many physiologic functions-as, indeed, do many of the inflammagens released in the inflammatory process. Here, we introduce the reader to the role of these ionotropic receptors in mediating peripheral pain in response to inflammation.


2019 ◽  
Vol 20 (10) ◽  
pp. 2371 ◽  
Author(s):  
J. Antonio Lamas ◽  
Lola Rueda-Ruzafa ◽  
Salvador Herrera-Pérez

Controlling body temperature is a matter of life or death for most animals, and in mammals the complex thermoregulatory system is comprised of thermoreceptors, thermosensors, and effectors. The activity of thermoreceptors and thermoeffectors has been studied for many years, yet only recently have we begun to obtain a clear picture of the thermosensors and the molecular mechanisms involved in thermosensory reception. An important step in this direction was the discovery of the thermosensitive transient receptor potential (TRP) cationic channels, some of which are activated by increases in temperature and others by a drop in temperature, potentially converting the cells in which they are expressed into heat and cold receptors. More recently, the TWIK-related potassium (TREK) channels were seen to be strongly activated by increases in temperature. Hence, in this review we want to assess the hypothesis that both these groups of channels can collaborate, possibly along with other channels, to generate the wide range of thermal sensations that the nervous system is capable of handling.


2021 ◽  
Vol 22 (14) ◽  
pp. 7591
Author(s):  
Qiaojuan Zhang ◽  
Gwendolyn Henry ◽  
Yong Chen

Itch is a clinical problem that leaves many sufferers insufficiently treated, with over 20 million cases in the United States. This is due to incomplete understanding of its molecular, cellular, and cell-to-cell signaling mechanisms. Transient receptor potential (TRP) ion channels are involved in several sensory modalities including pain, vision, taste, olfaction, hearing, touch, and thermosensation, as well as itch. Relative to the extensive studies on TRPV1 and TRPA1 ion channels in itch modulation, TRPV4 has received relatively little research attention and its mechanisms have remained poorly understood until recently. TRPV4 is expressed in ganglion sensory neurons and a variety of skin cells. Growing evidence in the past few years strongly suggests that TRPV4 in these cells contributes to acute and chronic disease-associated itch. This review focuses on the current experimental evidence involving TRPV4 in itch under pathophysiological conditions and discusses its possible cellular and molecular mechanisms.


2021 ◽  
pp. 363-381
Author(s):  
V SINICA ◽  
V VLACHOVÁ

The discovery of the role of the transient receptor potential ankyrin 1 (TRPA1) channel as a polymodal detector of cold and pain-producing stimuli almost two decades ago catalyzed the consequent identification of various vertebrate and invertebrate orthologues. In different species, the role of TRPA1 has been implicated in numerous physiological functions, indicating that the molecular structure of the channel exhibits evolutionary flexibility. Until very recently, information about the critical elements of the temperature-sensing molecular machinery of thermosensitive ion channels such as TRPA1 had lagged far behind information obtained from mutational and functional analysis. Current developments in single-particle cryo-electron microscopy are revealing precisely how the thermosensitive channels operate, how they might be targeted with drugs, and at which sites they can be critically regulated by membrane lipids. This means that it is now possible to resolve a huge number of very important pharmacological, biophysical and physiological questions in a way we have never had before. In this review, we aim at providing some of the recent knowledge on the molecular mechanisms underlying the temperature sensitivity of TRPA1. We also demonstrate how the search for differences in temperature and chemical sensitivity between human and mouse TRPA1 orthologues can be a useful approach to identifying important domains with a key role in channel activation.


2010 ◽  
Vol 2 (2) ◽  
pp. 51-60 ◽  
Author(s):  
Masayuki TAKEDA ◽  
Tsutomu MOCHIZUKI ◽  
Mitsuharu YOSHIYAMA ◽  
Hiroshi NAKAGOMI ◽  
Hideki KOBAYASHI ◽  
...  

Cancers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 322 ◽  
Author(s):  
Giorgio Santoni ◽  
Consuelo Amantini

Recently, the finding of cancer stem cells in brain tumors has increased the possibilitiesfor advancing new therapeutic approaches with the aim to overcome the limits of current availabletreatments. In addition, a role for ion channels, particularly of TRP channels, in developing neuronsas well as in brain cancer development and progression have been demonstrated. Herein, we focuson the latest advancements in understanding the role of TRPV2, a Ca2+ permeable channel belongingto the TRPV subfamily in neurogenesis and gliomagenesis. TRPV2 has been found to be expressedin both neural progenitor cells and glioblastoma stem/progenitor-like cells (GSCs). In developingneurons, post-translational modifications of TRPV2 (e.g., phosphorylation by ERK2) are required tostimulate Ca2+ signaling and nerve growth factor-mediated neurite outgrowth. TRPV2overexpression also promotes GSC differentiation and reduces gliomagenesis in vitro and in vivo.In glioblastoma, TRPV2 inhibits survival and proliferation, and induces Fas/CD95-dependentapoptosis. Furthermore, by proteomic analysis, the identification of a TRPV2 interactome-basedsignature and its relation to glioblastoma progression/recurrence, high or low overall survival anddrug resistance strongly suggest an important role of the TRPV2 channel as a potential biomarkerin glioblastoma prognosis and therapy.


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