Chemosensory Transduction in Arthropods

Receptor Gene ◽

Olfactory Receptors ◽

Receptor Potential ◽

Gene Families ◽

Chemosensory Transduction ◽

Dependent Signal ◽

Transient Receptor ◽

Species Specific

Reception of chemicals via olfaction and gustation are prerequisites to find, distinguish, and recognize food and mates and to avoid dangers. Several receptor gene superfamilies are employed in arthropod chemosensation: inverse 7-transmembrane (7-TM) gustatory and olfactory receptors (GRs, ORs), 3-TM ionotropic glutamate-related receptors (IRs), receptor-guanylyl cyclases, transient receptor potential ion channels, and epithelial sodium channels. Some of these receptor gene families have ancient origins and expanded in several taxa, producing very large, variant gene families adapted to the respectively relevant odor ligands in species-specific environments. Biochemical and electrophysiological studies in situ as well as molecular genetics found evidence for G-protein-dependent signal transduction cascades for ORs, GRs, and IRs, suggesting that signal amplification is paramount for chemical senses. In contrast, heterologous expression studies argued for primarily ionotropic transduction as a prerequisite to interstimulus intervals in the range of microseconds.

The Na+/Ca2+ Exchanger Inhibitor, KB-R7943, Blocks a Nonselective Cation Channel Implicated in Chemosensory Transduction

Journal of Neurophysiology ◽

10.1152/jn.90903.2008 ◽

2009 ◽

Vol 101 (3) ◽

pp. 1151-1159 ◽

Cited By ~ 12

Author(s):

A. Pezier ◽

Y. V. Bobkov ◽

B. W. Ache

Keyword(s):

Single Channel ◽

Receptor Potential ◽

Trpc Channels ◽

Dependent Manner ◽

Open Probability ◽

Olfactory Transduction ◽

Voltage Dependent ◽

Chemosensory Transduction ◽

The mechanism(s) of olfactory transduction in invertebrates remains to be fully understood. In lobster olfactory receptor neurons (ORNs), a nonselective sodium-gated cation (SGC) channel, a presumptive transient receptor potential (TRP)C channel homolog, plays a crucial role in olfactory transduction, at least in part by amplifying the primary transduction current. To better determine the functional role of the channel, it is important to selectively block the channel independently of other elements of the transduction cascade, causing us to search for specific pharmacological blockers of the SGC channel. Given evidence that the Na+/Ca2+ exchange inhibitor, KB-R7943, blocks mammalian TRPC channels, we studied this probe as a potential blocker of the lobster SGC channel. KB-R7943 reversibly blocked the SGC current in both inside- and outside-out patch recordings in a dose- and voltage-dependent manner. KB-R7943 decreased the channel open probability without changing single channel amplitude. KB-R7943 also reversibly and in a dose-dependent manner inhibited both the odorant-evoked discharge of lobster ORNs and the odorant-evoked whole cell current. Our findings strongly imply that KB-R7943 potently blocks the lobster SGC channel and likely does so directly and not through its ability to block the Na+/Ca2+ exchanger.

Perivagal antagonist treatment in rats selectively blocks the reflex and afferent responses of vagal lung C fibers to intravenous agonists

Journal of Applied Physiology ◽

10.1152/japplphysiol.00977.2012 ◽

2013 ◽

Vol 114 (3) ◽

pp. 361-370 ◽

Cited By ~ 11

Author(s):

Yu-Jung Lin ◽

You Shuei Lin ◽

Ching Jung Lai ◽

Zung Fan Yuan ◽

Ting Ruan ◽

...

Keyword(s):

Receptor Potential ◽

Transient Receptor Potential Vanilloid ◽

Stimulatory Action ◽

Lung Inflation ◽

Intravenous Injections ◽

C Fibers ◽

Vehicle Treatment ◽

The terminals of vagal lung C fibers (VLCFs) express various types of pharmacological receptors that are important to the elicitation of airway reflexes and the development of airway hypersensitivity. We investigated the blockade of the reflex and afferent responses of VLCFs to intravenous injections of agonists using perivagal treatment with antagonists (PAT) targeting the transient receptor potential vanilloid 1, P2X, and 5-HT3 receptors in anesthetized rats. Blockading these responses via perivagal capsaicin treatment (PCT), which blocks the neural conduction of C fibers, was also studied. We used capsaicin, α,β-methylene-ATP, and phenylbiguanide as the agonists, and capsazepine, iso-pyridoxalphosphate-6-azophenyl-2′,5′-disulfonate, and tropisetron as the antagonists of transient receptor potential vanilloid 1, P2X, and 5-HT3 receptors, respectively. We found that each of the PATs abolished the VLCF-mediated reflex apnea evoked by the corresponding agonist, while having no effect on the response to other agonists. Perivagal vehicle treatment failed to produce any such blockade. These blockades had partially recovered at 3 h after removal of the PATs. In contrast, PCT abolished the reflex apneic response to all three agonists. Both PATs and PCT did not affect the myelinated afferent-mediated apneic response to lung inflation. Consistently, our electrophysiological studies revealed that each of the PATs prevented the VLCF responses to the corresponding agonist, but not to any other agonist. PCT inevitably prevented the VLCF responses to all three agonists. Thus these PATs selectively blocked the stimulatory action of corresponding agonists on the VLCF terminals via mechanisms that are distinct from those of PCT. PAT may become a novel intervention for studying the pharmacological modulation of VLCFs.

Regulatory switch at the cytoplasmic interface controls TRPV channel gating

eLife ◽

10.7554/elife.47746 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 18

Author(s):

Lejla Zubcevic ◽

William F Borschel ◽

Allen L Hsu ◽

Mario J Borgnia ◽

Seok-Yong Lee

Keyword(s):

Receptor Potential ◽

Transient Receptor Potential Vanilloid ◽

Temperature Sensitive ◽

Physiological Processes ◽

Physiological Properties ◽

Transient Receptor ◽

Large Rearrangements

Temperature-sensitive transient receptor potential vanilloid (thermoTRPV) channels are activated by ligands and heat, and are involved in various physiological processes. ThermoTRPV channels possess a large cytoplasmic ring consisting of N-terminal ankyrin repeat domains (ARD) and C-terminal domains (CTD). The cytoplasmic inter-protomer interface is unique and consists of a CTD coiled around a β-sheet which makes contacts with the neighboring ARD. Despite much existing evidence that the cytoplasmic ring is important for thermoTRPV function, the mechanism by which this unique structure is involved in thermoTRPV gating has not been clear. Here, we present cryo-EM and electrophysiological studies which demonstrate that TRPV3 gating involves large rearrangements at the cytoplasmic inter-protomer interface and that this motion triggers coupling between cytoplasmic and transmembrane domains, priming the channel for opening. Furthermore, our studies unveil the role of this interface in the distinct biophysical and physiological properties of individual thermoTRPV subtypes.

Drosophila sensory receptors—a set of molecular Swiss Army Knives

Genetics ◽

10.1093/genetics/iyaa011 ◽

2021 ◽

Vol 217 (1) ◽

pp. 1-34 ◽

Cited By ~ 1

Author(s):

Craig Montell

Keyword(s):

Olfactory Receptors ◽

Receptor Potential ◽

Fruit Fly ◽

Transient Receptor Potential Channels ◽

Sensory Receptors ◽

Gustatory Receptors ◽

Ionotropic Receptors ◽

Potential Channels ◽

Abstract Genetic approaches in the fruit fly, Drosophila melanogaster, have led to a major triumph in the field of sensory biology—the discovery of multiple large families of sensory receptors and channels. Some of these families, such as transient receptor potential channels, are conserved from animals ranging from worms to humans, while others, such as “gustatory receptors,” “olfactory receptors,” and “ionotropic receptors,” are restricted to invertebrates. Prior to the identification of sensory receptors in flies, it was widely assumed that these proteins function in just one modality such as vision, smell, taste, hearing, and somatosensation, which includes thermosensation, light, and noxious mechanical touch. By employing a vast combination of genetic, behavioral, electrophysiological, and other approaches in flies, a major concept to emerge is that many sensory receptors are multitaskers. The earliest example of this idea was the discovery that individual transient receptor potential channels function in multiple senses. It is now clear that multitasking is exhibited by other large receptor families including gustatory receptors, ionotropic receptors, epithelial Na+ channels (also referred to as Pickpockets), and even opsins, which were formerly thought to function exclusively as light sensors. Genetic characterizations of these Drosophila receptors and the neurons that express them also reveal the mechanisms through which flies can accurately differentiate between different stimuli even when they activate the same receptor, as well as mechanisms of adaptation, amplification, and sensory integration. The insights gleaned from studies in flies have been highly influential in directing investigations in many other animal models.

STRUCTURE, PROPERTIES AND PHYSIOLOGICAL ROLE OF TRPA1 RECEPTORS

Fiziolohichnyĭ zhurnal ◽

10.15407/fz67.01.044 ◽

2021 ◽

Vol 67 (1) ◽

pp. 44-56

Author(s):

M.A. Petrushenko ◽

◽

E.A. Petrushenko ◽

E.A. Lukyanetz ◽

◽

...

Keyword(s):

Receptor Gene ◽

Experimental Studies ◽

Physiological Role ◽

Receptor Potential ◽

Transient Receptor ◽

Peripheral Sensory ◽

Structure Properties

In mammals, the ankyrin ionotropic transient receptor potential type 1 (TRPA1) is the only member of the TRPA receptor gene subfamily. It is defined as a target for damaging and inflammatory effects in peripheral sensory neurons, which implies its functional role in the development of pain and neurogenic inflammation. Experimental studies indicate that calcium permeable non-selective ion receptor channel TRPA1 is activated by a number of exogenous irritant compounds, factors including low temperatures. This review describes the structure, properties, and physiological role of TRPA1 receptors.

The evolution and comparative neurobiology of endocannabinoid signalling

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2011.0394 ◽

2012 ◽

Vol 367 (1607) ◽

pp. 3201-3215 ◽

Cited By ~ 81

Author(s):

Maurice R. Elphick

Keyword(s):

Cannabinoid Receptors ◽

Receptor Potential ◽

System Level ◽

Transient Receptor Potential Vanilloid ◽

Sea Squirt ◽

Neuronal Signalling ◽

Retrograde Signalling ◽

CB 1 - and CB 2 -type cannabinoid receptors mediate effects of the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide in mammals. In canonical endocannabinoid-mediated synaptic plasticity, 2-AG is generated postsynaptically by diacylglycerol lipase alpha and acts via presynaptic CB 1 -type cannabinoid receptors to inhibit neurotransmitter release. Electrophysiological studies on lampreys indicate that this retrograde signalling mechanism occurs throughout the vertebrates, whereas system-level studies point to conserved roles for endocannabinoid signalling in neural mechanisms of learning and control of locomotor activity and feeding. CB 1 /CB 2 -type receptors originated in a common ancestor of extant chordates, and in the sea squirt Ciona intestinalis a CB 1 /CB 2 -type receptor is targeted to axons, indicative of an ancient role for cannabinoid receptors as axonal regulators of neuronal signalling. Although CB 1 /CB 2 -type receptors are unique to chordates, enzymes involved in biosynthesis/inactivation of endocannabinoids occur throughout the animal kingdom. Accordingly, non-CB 1 /CB 2 -mediated mechanisms of endocannabinoid signalling have been postulated. For example, there is evidence that 2-AG mediates retrograde signalling at synapses in the nervous system of the leech Hirudo medicinalis by activating presynaptic transient receptor potential vanilloid-type ion channels. Thus, postsynaptic synthesis of 2-AG or anandamide may be a phylogenetically widespread phenomenon, and a variety of proteins may have evolved as presynaptic (or postsynaptic) receptors for endocannabinoids.

The crystal structure of TRPM2 MHR1/2 domain reveals a conserved Zn2+-binding domain essential for ligand binding and activity

10.1101/2022.01.04.474898 ◽

2022 ◽

Author(s):

Simon Sander ◽

Ellen Gattkowski ◽

Jelena Pick ◽

Ralf Fliegert ◽

Henning Tidow

Keyword(s):

Crystal Structure ◽

Specific Binding ◽

Receptor Potential ◽

Binding Domain ◽

Dependent Manner ◽

Structural Element ◽

Transient Receptor Potential Melastatin ◽

Transient Receptor ◽

Species Specific

Transient receptor potential melastatin 2 (TRPM2) is a Ca2+-permeable, non-selective cation channel involved in diverse physiological processes such as immune response, apoptosis and body temperature sensing. TRPM2 is activated by ADP-ribose (ADPR) and 2′-deoxy-ADPR in a Ca2+-dependent manner. While two species-specific binding sites exist for ADPR, a binding site for 2′-deoxy-ADPR is not known yet. Here, we report the crystal structure of the MHR1/2 domain of TRPM2 from zebrafish (Danio rerio) and show binding of both ligands to this domain. We identified a so-far unrecognized Zn2+-binding domain that was not resolved in previous cryo-EM structures and that is conserved in most TRPM channels. In combination with patch clamp experiments, we comprehensively characterize the effect of the Zn2+-binding domain on TRPM2 activation. Our results provide insight into a conserved structural element essential for channel activity.

A transcriptomic atlas of mammalian olfactory mucosae reveals an evolutionary influence on food odor detection in humans

10.1101/552232 ◽

2019 ◽

Author(s):

Luis R. Saraiva ◽

Fernando Riveros-McKay ◽

Massimo Mezzavilla ◽

Eman H. Abou-Moussa ◽

Charles J. Arayata ◽

...

Keyword(s):

Evolutionary Dynamics ◽

Dynamic Range ◽

Receptor Gene ◽

Olfactory Receptors ◽

Gene Families ◽

Ecological Niches ◽

Mammalian Evolution ◽

Large Dynamic Range ◽

Species Specific ◽

Sensory Profiles

ABSTRACTThe mammalian olfactory system displays species-specific adaptations to different ecological niches. To investigate the evolutionary dynamics of olfactory sensory neuron (OSN) sub-types across 95 million years of mammalian evolution, we applied RNA-sequencing of whole olfactory mucosa samples from mouse, rat, dog, marmoset, macaque and human. We find that OSN subtypes representative of all known mouse chemosensory receptor gene families are present in all analyzed species. Further, we show that OSN subtypes expressing canonical olfactory receptors (ORs) are distributed across a large dynamic range and that homologous subtypes can be either highly abundant across all species or species/order-specific. Interestingly, highly abundant mouse and human OSN subtypes detect odorants with similar sensory profiles, and sense ecologically relevant odorants, such as mouse semiochemicals or human key food odorants. Taken together, our results allow for a better understanding of the evolution of mammalian olfaction in mammals and provide insights into the possible functions of highly abundant OSN subtypes in mouse and human.

A transcriptomic atlas of mammalian olfactory mucosae reveals an evolutionary influence on food odor detection in humans

Science Advances ◽

10.1126/sciadv.aax0396 ◽

2019 ◽

Vol 5 (7) ◽

pp. eaax0396 ◽

Cited By ~ 18

Author(s):

Luis R. Saraiva ◽

Fernando Riveros-McKay ◽

Massimo Mezzavilla ◽

Eman H. Abou-Moussa ◽

Charles J. Arayata ◽

...

Keyword(s):

Evolutionary Dynamics ◽

Dynamic Range ◽

Receptor Gene ◽

Olfactory Receptors ◽

Gene Families ◽

Ecological Niches ◽

Mammalian Evolution ◽

Large Dynamic Range ◽

Species Specific ◽

Sensory Profiles

The mammalian olfactory system displays species-specific adaptations to different ecological niches. To investigate the evolutionary dynamics of olfactory sensory neuron (OSN) subtypes across mammalian evolution, we applied RNA sequencing of whole olfactory mucosa samples from mouse, rat, dog, marmoset, macaque, and human. We find that OSN subtypes, representative of all known mouse chemosensory receptor gene families, are present in all analyzed species. Further, we show that OSN subtypes expressing canonical olfactory receptors are distributed across a large dynamic range and that homologous subtypes can be either highly abundant across all species or species/order specific. Highly abundant mouse and human OSN subtypes detect odorants with similar sensory profiles and sense ecologically relevant odorants, such as mouse semiochemicals or human key food odorants. Together, our results allow for a better understanding of the evolution of mammalian olfaction in mammals and provide insights into the possible functions of highly abundant OSN subtypes.