Modulation Of Transient Receptor Potential Channels Research Articles

Neuron Modulation by Synergetic Management of Redox Status and Oxidative Stress.

The transient receptor potential (TRP) channel is a key sensor for diverse cellular stimuli, regulating the excitability of primary nociceptive neurons. Sensitization of the TRP channel can heighten pain sensitivity to innocuous or mildly noxious stimuli. Here, reversible modulation of TRP channels is achieved by controlling both the light-induced photoelectrochemical reaction to induce neuronal depolarization, and antioxidants for neuronal protection. It is based on a hybrid nanosystem, CZPN, created by coating CeO2 nanocrystals with the metalloporphyrin ZnTPyP. Light irradiation triggers an electrochemical response, with efficient electron injection from ZnTPyP to CeO2, converting Ce4+ into Ce3+ as antioxidants. Meanwhile, the charge migrates from surrounding O2 molecules to the hole-injected ZnTPyP*, giving rise to reactive oxygen species (ROS). This change in the redox environment sensitizes TRP channels, eliciting action potentials in primary rat neurons, and is partially blocked by pretreatment with capsazepine. The resulting CeO2-x, with a high Ce3+/Ce4+ ratio, can scavenge excessive ROS to prevent oxidative damage. The light-induced pain behaviors in mice pre-injected with CZPN are further confirmed. This work suggests a safe, effective, and universal approach to photoelectrochemical processes for modulation and research of the peripheral nervous system.

Efficacy and safety of transient receptor potential channel modulators for dry eye: A systematic review and meta-analysis

Efficacy and safety of transient receptor potential channel modulators for dry eye: A systematic review and meta-analysis

Transient receptor potential channels as an emerging target for the treatment of Alzheimer's disease: Unravelling the potential of pharmacological interventions.

Alzheimer's disease (AD) is a devastating disorder with a multifaceted aetiology characterized by dementia, which later progresses to cognitive impairment. Significant efforts have been made to develop pharmacological interventions that slow down the pathogenesis of AD. However, conventional drugs have failed to satisfactorily treat AD and are more focussed towards symptomatic management. Thus, there is a gap in the literature regarding novel targets and modulators targeting them for the effective treatment of AD. Recent studies have demonstrated that modulation of transient receptor potential (TRP) channels has the potential to halt AD pathogenesis at an early stage and rescue hippocampal neurons from death. Amongst several members, TRP channels like TRPA1, TRPC6, TRPM2 and TRPV2 have shown promising results in the attenuation of neurobehavioural cognitive deficits as well as signalling pathways governing such cognitive decline. Furthermore, as these channels govern the ionic balance in the cell, their beneficial effects have also been known to maintain the homeostasis of Ca2+, which is the major culprit eliciting the vicious cycle of excitotoxicity, mitochondrial dysfunction, ROS generation and neurodegeneration. Despite such tremendous potential of TRP channel modulators, their clinical investigation remains elusive. Therefore, in the present review, we have discussed such agents in the light of TRP channels as molecular targets for the amelioration of AD both at the preclinical and clinical levels.

Bromelain regulates TRP channels to induce orofacial nociception relief in adult zebrafish

Bromelain, the main protease enzyme found in the pineapple plant (Ananas comosus), has had its antinociceptive effect previously demonstrated. This investigation aimed to appraise the role of TRP (Transient Receptor Potential) channels in the nociception-relieving effects of bromelain in the orofacial region of adult zebrafish. The animals were pretreated with bromelain (3.0, 10.0 or 30.0 mg/mL; gavage) and submitted to open field and acute orofacial (capsaicin - TRPV1 agonist, cinnamaldehyde - TRPA1 agonist or menthol - TRPM8 agonist) nociception tests. The investigation also explored the contribution of central afferent C-fibers. Naive groups were included for comparison. Bromelain did not independently affect the zebrafish movement patterns. However, bromelain decreased the nociceptive responses elicited by all three TRP channel activators. Capsazepine (TRPV1 inhibitor) and AMTB (TRPM8 inhibitor), but not HC-030031 (TRPA1 inhibitor), prevented the antinociceptive effect of bromelain. Moreover, capsaicin-induced desensitization effectively nullified the antinociceptive effect of bromelain. Collectively, these findings corroborate the therapeutic relevance of bromelain as a suppressor of orofacial nociception, which seems to be intricately connected to the modulation of TRP channels.

Investigations into hydrogen sulfide-induced suppression of neuronal activity in vivo and calcium dysregulation in vitro.

Acute exposure to high concentrations of hydrogen sulfide (H2S) leads to sudden death and, if survived, lingering neurological disorders. Clinical signs include seizures, loss of consciousness, and dyspnea. The proximate mechanisms underlying H2S-induced acute toxicity and death have not been clearly elucidated. We investigated electrocerebral, cardiac and respiratory activity during H2S exposure using electroencephalogram (EEG), electrocardiogram (EKG) and plethysmography. H2S suppressed electrocerebral activity and disrupted breathing. Cardiac activity was comparatively less affected. To test whether Ca2+ dysregulation contributes to H2S-induced EEG suppression, we developed an in vitro real-time rapid throughput assay measuring patterns of spontaneous synchronized Ca2+ oscillations in cultured primary cortical neuronal networks loaded with the indicator Fluo-4 using the fluorescent imaging plate reader (FLIPR-Tetra®). Sulfide >5 ppm dysregulated synchronous calcium oscillation (SCO) patterns in a dose-dependent manner. Inhibitors of NMDA and AMPA receptors magnified H2S-induced SCO suppression. Inhibitors of L-type voltage gated Ca2+ channels and transient receptor potential channels prevented H2S-induced SCO suppression. Inhibitors of T-type voltage gated Ca2+ channels, ryanodine receptors, and sodium channels had no measurable influence on H2S-induced SCO suppression. Exposures to > 5 ppm sulfide also suppressed neuronal electrical activity in primary cortical neurons measured by multi-electrode array (MEA), an effect alleviated by pretreatment with the nonselective transient receptor potential channel inhibitor, 2-APB. 2-APB also reduced primary cortical neuronal cell death from sulfide exposure. These results improve our understanding of the role of different Ca2+ channels in acute H2S-induced neurotoxicity and identify transient receptor potential channel modulators as novel structures with potential therapeutic benefits.

Pharmacological Management of Dysphagia in Patients with Alzheimer's Disease: A Narrative Review.

Alzheimer's disease (AD) and dysphagia are important health and socioeconomic problems in the aging population. Currently, the medical treatment of dysphagia in AD patients remains insufficient, and there are significant gaps in the management and clinical needs to postpone tube feeding. Literatures published over the last 30 years were searched in the PubMed and Embase databases. All relevant and promising pharmacological management studies were included. Because of the heterogeneity in design and methodology, only narrative reports were mentioned. Nine studies were included with two case reports, two case series, and two observational and three randomized controlled trials. The key approaches and clinical problems related to dysphagia include onset pattern, dementia stage, review of offending drugs and polypharmacy, and comorbidities (cerebrovascular disease, hypertension, parkinsonism, depression, and anorexia). The corresponding strategies of pharmacological treatments are further proposed and discussed comprehensively, with transient receptor potential channel modulators as promising treatment. With the integration of adequate and potential pharmacomanagement, AD patients with dysphagia can achieve a good prognosis and postpone tube feeding to maintain a better quality of life. More rigorous studies are needed to verify the effectiveness of innovative strategies and develop targets for neurostimulation.

TRP Channels as Molecular Targets to Relieve Cancer Pain.

Transient receptor potential (TRP) channels are critical receptors in the transduction of nociceptive stimuli. The microenvironment of diverse types of cancer releases substances, including growth factors, neurotransmitters, and inflammatory mediators, which modulate the activity of TRPs through the regulation of intracellular signaling pathways. The modulation of TRP channels is associated with the peripheral sensitization observed in patients with cancer, which results in mild noxious sensory stimuli being perceived as hyperalgesia and allodynia. Secondary metabolites derived from plant extracts can induce the activation, blocking, and desensitization of TRP channels. Thus, these compounds could act as potential therapeutic agents, as their antinociceptive properties could be beneficial in relieving cancer-derived pain. In this review, we will summarize the role of TRPV1 and TRPA1 in pain associated with cancer and discuss molecules that have been reported to modulate these channels, focusing particularly on the mechanisms of channel activation associated with molecules released in the tumor microenvironment.

Spontaneous excitatory transmission enhancement produced by linalool and its isomer geraniol in rat spinal substantia gelatinosa neurons - involvement of transient receptor potential channels

BackgroundMany of plant-derived compounds inhibiting nerve conduction enhance glutamatergic spontaneous excitatory transmission by activating transient receptor potential (TRP) channels in spinal substantia gelatinosa (SG) neurons that play a crucial role in regulating nociceptive transmission. Although (±)-linalool and its isomer geraniol having antinociceptive effects inhibit nerve conduction, it has not been examined yet how they affect excitatory transmission in SG neurons. We examined the effects of the compounds on action potential-independent spontaneous excitatory transmission with a focus on an involvement of TRP channels. MethodsThe whole-cell patch-clamp technique was applied to SG neurons in adult rat spinal cord slices. Results(±)-Linalool increased the frequency of spontaneous excitatory postsynaptic current (sEPSC) with a small increase in its amplitude. The (±)-linalool activity was sensitive to TRP vanilloid-1 (TRPV1) antagonist capsazepine and TRP ankyrin-1 (TRPA1) antagonist HC-030,031 while resistant to BCTC that is antagonist for cloned TRPV1 and TRP melastatin-8 (TRPM8) channels and for TRPM8 channels in the SG, indicating TRPV1 and TRPA1 activation. In 73% of the neurons tested, (±)-linalool produced an outward current at -70 mV. In SG neurons sensitive to (±)-linalool, geraniol produced a quantitatively similar effect to (±)-linalool. Geraniol-induced sEPSC frequency increase was sensitive to BCTC but resistant to capsazepine and HC-030,031, indicating TRPM8 activation. Outward currents produced by (±)-linalool and geraniol were unaffected by all of the TRP antagonists. ConclusionIn SG neurons, (±)-linalool and geraniol presynaptically enhanced spontaneous excitatory transmission by activating different types of TRP channel while hyperpolarizing membranes in a manner independent of TRP channels. Such a TRP channel modulation and hyperpolarization could contribute to the antinociceptive effects of (±)-linalool and geraniol.

Advances in TRP channel drug discovery: from target validation to clinical studies.

Transient receptor potential (TRP) channels are multifunctional signalling molecules with many roles in sensory perception and cellular physiology. Therefore, it is not surprising that TRP channels have been implicated in numerous diseases, including hereditary disorders caused by defects in genes encoding TRP channels (TRP channelopathies). Most TRP channels are located at the cell surface, which makes them generally accessible drug targets. Early drug discovery efforts to target TRP channels focused on pain, but as our knowledge of TRP channels and their role in health and disease has grown, these efforts have expanded into new clinical indications, ranging from respiratory disorders through neurological and psychiatric diseases to diabetes and cancer. In this Review, we discuss recent findings in TRP channel structural biology that can affect both drug development and clinical indications. We also discuss the clinical promise of novel TRP channel modulators, aimed at both established and emerging targets. Last, we address the challenges that these compounds may face in clinical practice, including the need for carefully targeted approaches to minimize potential side-effects due to the multifunctional roles of TRP channels.

Th2 Modulation of Transient Receptor Potential Channels: An Unmet Therapeutic Intervention for Atopic Dermatitis.

Atopic dermatitis (AD) is a multifaceted, chronic relapsing inflammatory skin disease that affects people of all ages. It is characterized by chronic eczema, constant pruritus, and severe discomfort. AD often progresses from mild annoyance to intractable pruritic inflammatory lesions associated with exacerbated skin sensitivity. The T helper-2 (Th2) response is mainly linked to the acute and subacute phase, whereas Th1 response has been associated in addition with the chronic phase. IL-17, IL-22, TSLP, and IL-31 also play a role in AD. Transient receptor potential (TRP) cation channels play a significant role in neuroinflammation, itch and pain, indicating neuroimmune circuits in AD. However, the Th2-driven cutaneous sensitization of TRP channels is underappreciated. Emerging findings suggest that critical Th2-related cytokines cause potentiation of TRP channels, thereby exaggerating inflammation and itch sensation. Evidence involves the following: (i) IL-13 enhances TRPV1 and TRPA1 transcription levels; (ii) IL-31 sensitizes TRPV1 via transcriptional and channel modulation, and indirectly modulates TRPV3 in keratinocytes; (iii) The Th2-cytokine TSLP increases TRPA1 synthesis in sensory neurons. These changes could be further enhanced by other Th2 cytokines, including IL-4, IL-25, and IL-33, which are inducers for IL-13, IL-31, or TSLP in skin. Taken together, this review highlights that Th2 cytokines potentiate TRP channels through diverse mechanisms under different inflammatory and pruritic conditions, and link this effect to distinct signaling cascades in AD. This review strengthens the notion that interrupting Th2-driven modulation of TRP channels will inhibit transition from acute to chronic AD, thereby aiding the development of effective therapeutics and treatment optimization.

Ascorbate-induced oxidative stress mediates TRP channel activation and cytotoxicity in human etoposide-sensitive and -resistant retinoblastoma cells

AbstractThere are indications that pharmacological doses of ascorbate (Asc) used as an adjuvant improve the chemotherapeutic management of cancer. This favorable outcome stems from its cytotoxic effects due to prooxidative mechanisms. Since regulation of intracellular Ca2+ levels contributes to the maintenance of cell viability, we hypothesized that one of the effects of Asc includes disrupting regulation of intracellular Ca2+ homeostasis. Accordingly, we determined if Asc induced intracellular Ca2+ influx through activation of pertussis sensitive Gi/o-coupled GPCR which in turn activated transient receptor potential (TRP) channels in both etoposide-resistant and -sensitive retinoblastoma (WERI-Rb1) tumor cells. Ca2+ imaging, whole-cell patch-clamping, and quantitative real-time PCR (qRT-PCR) were performed in parallel with measurements of RB cell survival using Trypan Blue cell dye exclusion. TRPM7 gene expression levels were similar in both cell lines whereas TRPV1, TRPM2, TRPA1, TRPC5, TRPV4, and TRPM8 gene expression levels were downregulated in the etoposide-resistant WERI-Rb1 cells. In the presence of extracellular Ca2+, 1 mM Asc induced larger intracellular Ca2+ transients in the etoposide-resistant WERI-Rb1 than in their etoposide-sensitive counterpart. With either 100 µM CPZ, 500 µM La3+, 10 mM NAC, or 100 µM 2-APB, these Ca2+ transients were markedly diminished. These inhibitors also had corresponding inhibitory effects on Asc-induced rises in whole-cell currents. Pertussis toxin (PTX) preincubation blocked rises in Ca2+ influx. Microscopic analyses showed that after 4 days of exposure to 1 mM Asc cell viability fell by nearly 100% in both RB cell lines. Taken together, one of the effects underlying oxidative mediated Asc-induced WERI-Rb1 cytotoxicity stems from its promotion of Gi/o coupled GPCR mediated increases in intracellular Ca2+ influx through TRP channels. Therefore, designing drugs targeting TRP channel modulation may be a viable approach to increase the efficacy of chemotherapeutic treatment of RB. Furthermore, Asc may be indicated as a possible supportive agent in anti-cancer therapies.Ascorbate can act as an oxidant to induce tumor cell death at a pharmacological dose. Here the authors show that this response is associated with increases in GPCR Gi/o activity. This effect promotes rises in intracellular Ca2+ influx through transient receptor potential channel activity in retinoblastoma cells.

Modulation of Transient Receptor Potential (TRP) channels by tyrosine phosphorylation

Transient Receptor Potential (TRP) channels are a superfamily of polymodal, non-selective receptors, expressed in the nervous system and several other tissues, where they play many physiological or pathological roles. TRP channels are sensitive to a diverse range of stimuli, such as temperature, osmolarity, oxidative stress, external compounds and intracellular signaling molecules. The activity of TRP channels can be modulated by protein phosphorylation, including tyrosine phosphorylation. In this review, we present the studies carried out so far regarding the modulation of TRP channels by tyrosine phosphorylation.

A Precise Microfluidic Assay in Single-Cell Profile for Screening of Transient Receptor Potential Channel Modulators.

Transient receptor potential (TRP) channels are emerging drug targets, and TRP channel modulators possess therapeutic potential for many indications. However, there is a lack of intellectual and robust screening assays against TRP channels utilizing the least amount of compounds. Here, a precise microfluidic assay in single‐cell profile is developed for the screening of TRP channel modulators. The geometrically optimized microchip is designed for both trapping single cells and utilizing passive pumping for sequential media replacement with low shear stress. The microfluidic chip exhibits superior performance in screening, repeatable compound administration, and improved reproducibility. Using this screening platform, the false‐positive and negative rate of the commonly used Ca2+ imaging is reduced from 76.2% to 4.8% and four coumarin derivatives isolated from Murraya species that inhibit TRP channels are identified. One coumarin derivative B‐304 reverses TRPA1‐mediated inflammatory pain in vivo. Taken together, the data demonstrate that the established microfluidic assay in single‐cell profile could be used for the screening of TRP channel modulators that may have therapeutic potential for the channelopathies.

Emerging Perspectives on Pain Management by Modulation of TRP Channels and ANO1.

Receptor-type ion channels are critical for detection of noxious stimuli in primary sensory neurons. Transient receptor potential (TRP) channels mediate pain sensations and promote a variety of neuronal signals that elicit secondary neural functions (such as calcitonin gene-related peptide [CGRP] secretion), which are important for physiological functions throughout the body. In this review, we focus on the involvement of TRP channels in sensing acute pain, inflammatory pain, headache, migraine, pain due to fungal infections, and osteo-inflammation. Furthermore, action potentials mediated via interactions between TRP channels and the chloride channel, anoctamin 1 (ANO1), can also generate strong pain sensations in primary sensory neurons. Thus, we also discuss mechanisms that enhance neuronal excitation and are dependent on ANO1, and consider modulation of pain sensation from the perspective of both cation and anion dynamics.

Potential therapeutic value of transient receptor potential channels in male urogenital system.

Transient receptor potential (TRP) channels comprise a family of cation channels implicated in a variety of cellular processes including light, mechanical or chemical stimuli, temperature, pH, or osmolarity. TRP channel proteins are a diverse family of proteins that are expressed in many tissues. We debated our recent knowledge about the expression, function, and regulation of TRP channels in the different parts of the male urogenital system in health and disease. Emerging evidence suggests that dysfunction ofTRP channels significantly contributes to the pathophysiology of urogenital diseases. So far, there are many efforts underway to determine if these channels can be used as drug targets to reverse declines in male urogenital function. Furthermore, developing safe and efficacious TRP channel modulators is warranted for male urogenital disorders in a clinical setting.

Transient receptor potential ion channel function in sensory transduction and cellular signaling cascades underlying visceral hypersensitivity.

Visceral hypersensitivity is an important mechanism underlying increased abdominal pain perception in functional gastrointestinal disorders including functional dyspepsia, irritable bowel syndrome, and inflammatory bowel disease in remission. Although the exact pathophysiological mechanisms are poorly understood, recent studies described upregulation and altered functions of nociceptors and their signaling pathways in aberrant visceral nociception, in particular the transient receptor potential (TRP) channel family. A variety of TRP channels are present in the gastrointestinal tract (TRPV1, TRPV3, TRPV4, TRPA1, TRPM2, TRPM5, and TRPM8), and modulation of their function by increased activation or sensitization (decreased activation threshold) or altered expression in visceral afferents have been reported in visceral hypersensitivity. TRP channels directly detect or transduce osmotic, mechanical, thermal, and chemosensory stimuli. In addition, pro-inflammatory mediators released in tissue damage or inflammation can activate receptors of the G protein-coupled receptor superfamily leading to TRP channel sensitization and activation, which amplify pain and neurogenic inflammation. In this review, we highlight the present knowledge on the functional roles of neuronal TRP channels in visceral hypersensitivity and discuss the signaling pathways that underlie TRP channel modulation. We propose that a better understanding of TRP channels and their modulators may facilitate the development of more selective and effective therapies to treat visceral hypersensitivity.

Atypical TRP Channel Pharmacology in Schistosomes

Parasitic flatworms of the genus Schistosoma cause schistosomiasis, a neglected tropical disease affecting over 200 million people. Only one drug is available for treatment and control, and there is an urgent need for new or repurposed antischistosomal agents. Ion channels are validated targets for current anthelmintics, but the roles and pharmacological sensitivities of transient receptor potential (TRP) channels are essentially unexplored in schistosomes and other parasitic helminths. We are using TRP channel modulators, RNA interference, and heterologous expression to examine the function and pharmacology of TRP channels in schistosomes. Though the S. mansoni genome predicts representatives of most TRP channel subfamilies, TRPV channels are notably absent. Despite this lack of TRPV-like channels, both adult and larval schistosomes exhibit dramatic hyperactivity in response to selective activators of mammalian TRPV1 such as capsaicin and resiniferatoxin. Capsaicin also causes rapid separation of paired adult males and females, perhaps indicative of a nociceptive response. The response to capsaicin is blocked by selective TRPV1 antagonists, further evidence for TRPV1-like pharmacology. Surprisingly, the capsaicin-induced hyperactivity in adult worms is virtually eliminated by knockdown of SmTRPA, a schistosome TRPA1-like channel. The TRPA1 activator AITC also elicits significant hyperactivity that is abolished by knockdown of SmTRPA1, indicating that SmTRPA exhibits mixed TRPV1/TRPA1-like pharmacology. Consistent with this hypothesis, exposure of SmTRPA-expressing mammalian cells to capsaicin or AITC elicits an influx of calcium, as measured by Fura-2 ratiometric imaging. These results suggest that some TRPV1-mediated sensory functions may be fulfilled by schistosome TRP channels from other subfamilies, and that at least one schistosome TRP channel has atypical pharmacological sensitivities that could be selectively targeted for development of new antischistosomal therapeutics. Other schistosome TRP channels might also be exploitable for targeting.

TRP channels: potential drug target for neuropathic pain

Neuropathic pain is a debilitating disease which affects central as well as peripheral nervous system. Transient receptor potential (TRP) channels are ligand-gated ion channels that detect physical and chemical stimuli and promote painful sensations via nociceptor activation. TRP channels have physiological role in the mechanisms controlling several physiological responses like temperature and mechanical sensations, response to painful stimuli, taste, and pheromones. TRP channel family involves six different TRPs (TRPV1, TRPV2, TRPV3, TRPV4, TRPM8, and TRPA1) which are expressed in pain sensing neurons and primary afferent nociceptors. They function as transducers for mechanical, chemical, and thermal stimuli into inward currents, an essential first step for provoking pain sensations. TRP ion channels activated by temperature (thermo TRPs) are important molecular players in acute, inflammatory, and chronic pain states. Different degree of heat activates four TRP channels (TRPV1-4), while cold temperature ranging from affable to painful activate two indistinctly related thermo TRP channels (TRPM8 and TRPA1). Targeting primary afferent nociceptive neurons containing TRP channels that play pivotal role in revealing physical stimuli may be an effective target for the development of successful pharmacotherapeutics for clinical pain syndromes. In this review, we highlighted the potential role of various TRP channels in different types of neuropathic pain. We also discussed the pharmacological activity of naturally and synthetically originated TRP channel modulators for pharmacotherapeutics of nociception and neuropathic pain.

Binding of Capsaicin to the TRPV1 Ion Channel.

Transient receptor potential (TRP) ion channels constitute a notable family of cation channels involved in the ability of an organisms to detect noxious mechanical, thermal, and chemical stimuli that give rise to the perception of pain, taste, and changes in temperature. One of the most experimentally studied agonist of TRP channels is capsaicin, which is responsible for the burning sensation produced when chili pepper is in contact with organic tissues. Thus, understanding how this molecule interacts and regulates TRP channels is essential to high impact pharmacological applications, particularly those related to pain treatment. The recent publication of a three-dimensional structure of the vanilloid receptor 1 (TRPV1) in the absence and presence of capsaicin from single particle electron cryomicroscopy experiments provides the opportunity to explore these questions at the atomic level. In the present work, molecular docking and unbiased and biased molecular dynamics simulations were employed to generate a structural model of the capsaicin-channel complex. In addition, the standard free energy of binding was estimated using alchemical transformations coupled with conformational, translational, and orientational restraints on the ligand. Key binding modes consistent with previous experimental data are identified, and subtle but essential dynamical features of the binding site are characterized. These observations shed some light into how TRPV1 interacts with capsaicin, and may help to refine design parameters for new TRPV1 antagonists, and potentially guide further developments of TRP channel modulators.

Understanding thermosensitive transient receptor potential channels as versatile polymodal cellular sensors.

Transient receptor potential (TRP) ion channels are eukaryotic polymodal sensors that function as molecular cellular signal integrators. TRP family members sense and are modulated by a wide array of inputs, including temperature, pressure, pH, voltage, chemicals, lipids, and other proteins. These inputs induce signal transduction events mediated by nonselective cation passage through TRP channels. In this review, we focus on the thermosensitive TRP channels and highlight the emerging view that these channels play a variety of significant roles in physiology and pathophysiology in addition to sensory biology. We attempt to use this viewpoint as a framework to understand the complexity and controversy of TRP channel modulation and ultimately suggest that the complex functional behavior arises inherently because this class of protein is exquisitely sensitive to many diverse and distinct signal inputs. To illustrate this idea, we primarily focus on TRP channel thermosensing. We also offer a structural, biochemical, biophysical, and computational perspective that may help to bring more coherence and consensus in understanding the function of this important class of proteins.