TRPA1 channels mediate cold temperature sensing in mammalian vagal sensory neurons: Pharmacological and genetic evidence

Cold thermoreceptors have been described in different territories of the vagus nerve. Application of cold temperature to these visceral afferents can evoke major protective reflexes and thermoregulatory responses. However, virtually nothing is known about the transduction mechanisms underlying cold sensitivity in vagal afferents. Here, we investigated the effects of cold stimulation on intracellular calcium responses and excitability of cultured vagal sensory neurons in the rat nodose ganglion. A large fraction of vagal neurons were activated by cold, with a mean threshold of ∼24°C. Cooling was accompanied by development of a small inward current and the firing of action potentials. Most cold-sensitive neurons were also activated by heat and capsaicin, suggesting a nociceptive function. The pharmacological response to TRPM8 and TRPA1 agonists and antagonists suggested that, unlike results observed in somatic tissues, TRPA1 is the major mediator of cold-evoked responses in vagal visceral neurons. Thus, most cold-evoked responses were potentiated by cinnamaldehyde, menthol, icilin, and BCTC [4-(3-chloro-pyridin-2-yl)-piperazine- 1-carboxylic acid (4-tert-butyl-phenyl)-amide], agonists of TRPA1, and were inhibited by ruthenium red, camphor, and HC03001 [2-(1,3-dimethyl-2,6-dioxo-1,2, 3,6-tetrahydro-7H-purin-7-yl)-N-(4-isopropylphenyl)acetamide]. Results in mouse nodose neurons revealed a similar pharmacological profile of cold-evoked responses. Furthermore, experiments in TRPA1 knock-out mice showed a large reduction in the percentage of cold-sensitive neurons compared with wild-type animals. Together, these results support an important role of TRPA1 channels in visceral thermosensation and indicate major differences in the transduction of temperature signals between somatic and visceral sensory neurons. Copyright © 2008 Society for Neuroscience.This work was supported by Spanish Ministry of Education and Science Project Grants BFU2007-61855 (F.V.) and BFU2005-08741 (C.B.), and Consolider-Ingenio 2010 Grant CSD2007-00023 (C.B.). O.F. and V.M were supported by predoctoral fellowships from the Spanish Consejo Superior de Investigaciones Científicas and the Generalitat Valenciana.Peer Reviewe

Variable threshold of trigeminal cold-thermosensitive neurons is determined by a balance between TRPM8 and Kv1 potassium channels

Molecular determinants of threshold differences among cold thermoreceptors are unknown. Here we show that such differences correlate with the relative expression of IKD, a current dependent on Shaker-like Kv1 channels that acts as an excitability brake, and ITRPM8, a cold-activated excitatory current. Neurons responding to small temperature changes have high functional expression of TRPM8 (transient receptor potential cation channel, subfamily M, member 8) and low expression of IKD. In contrast, neurons activated by lower temperatures have a lower expression of TRPM8 and a prominent IKD. Otherwise, both subpopulations have nearly identical membrane and firing properties, suggesting that they belong to the same neuronal pool. Blockade of IKD shins the threshold of cold-sensitive neurons to higher temperatures and augments cold-evoked nocifensive responses in mice. Similar behavioral effects of IKD blockade were observed in TRPA1-/- mice. Moreover, only a small percentage of trigeminal cold-sensitive neurons were activated by TRPA1 agonists, suggesting that TRPA1 does not play a major role in the detection of low temperatures by uninjured somatic cold-specific thermosensory neurons under physiological conditions. Collectively, these findings suggest that innocuous cooling sensations and cold discomfort are signaled by specific low- and high-threshold cold thermoreceptor neurons, differing primarily in their relative expression of two ion channels having antagonistic effects on neuronal excitability. Thus, although TRPM8 appears to function as a critical cold sensor in the majority of peripheral sensory neurons, the expression of Kv1 channels in the same terminals seem to play an important role in the peripheral gating of cold-evoked discomfort and pain. Copyright © 2009 Society for Neuroscience.This work was supported by funds from the Spanish Ministry of Education and Science: Projects BFU2007-61855 to F.V., and BFU2005-08741 and CONSOLIDER-INGENIO 2010 CSD2007-00023 to C.B., and the Spanish Fundación Marcelino BotínPeer Reviewe

The Augmented and Integrative Model of Economic Growth: Theoretical and Empirical Evidence from USA

[Abstract]: The current nexus between education and economic growth leads us to propose a hybrid and integrated theoretical model. The variables chosen for this research were human capital and labour, and their impact on unemployment and economic growth was considered. In the validation of the theoretical model, different equations were contemplated, and the ARDL cointegration technique for its estimation was chosen. This study emphasizes the importance of technological progress, physical capital and human capital; the latter is measured by educational training and its interactive effect on employment and unemployment in explaining the behaviour of economic growth in the US from 1981-2019. The results show different statistica significance in the short and long term. These results corroborate the premise that there are partial adjustments in the short term, particularly after an economic crisis. In the long term, economic growth is affected by the positive or negative magnitudes of the product elasticity for each of the drivers considered. In terms of policy implications, a combination of structural and demand-driven policies must be implemented to reduce unemployment, in particular, to halt protracted economic recessions

Differential role of the menthol-binding residue Y745 in the antagonism of thermally gated TRPM8 channels

<p>Abstract</p> <p>Background</p> <p>TRPM8 is a non-selective cation channel that belongs to the melastatin subfamily of the transient receptor potential (TRP) ion channels. TRPM8 is activated by voltage, cold and cooling compounds such as menthol. Despite its essential role for cold temperature sensing in mammals, the pharmacology of TRPM8 is still in its infancy. Recently, tyrosine 745 (Y745) was identified as a critical residue for menthol sensitivity of the channel. In this report, we study the effect of mutating this residue on the action of several known TRPM8 antagonists: BCTC, capsazepine, SKF96365, and clotrimazole as well as two new inhibitor candidates, econazole and imidazole.</p> <p>Results</p> <p>We show that Y745 at the menthol binding site is critical for inhibition mediated by SKF96365 of cold- and voltage-activated TRPM8 currents. In contrast, the inhibition by other antagonists was unaffected by the mutation (BCTC) or only partially reduced (capsazepine, clotrimazole, econazole), suggesting that additional binding sites exist on the TRPM8 channel from where the inhibitors exert their negative modulation. Indeed, a molecular docking model implies that menthol and SKF96365 interact readily with Y745, while BCTC is unable to bind to this residue.</p> <p>Conclusion</p> <p>In summary, we identify structural elements on the TRPM8 channel that are critical for the action of channel antagonists, providing valuable information for the future design of new, specific modulator compounds.</p

Drug discovery and computational strategies in the multitarget drugs era

The pharmaceutical industry is increasingly joining chemoinformatics in the search for the development of new drugs to be used in the treatment of diseases. These computational studies have the advantage of being less expensive and optimize the study time, and thus the interest in this area is increasing. Among the techniques used is the development of multitarget directed ligands (MTDLs), which has become an ascending technique, mainly due to the improvement in the quality of treatment involving several drugs. Multitarget therapy is more effective than traditional drug therapy that emphasizes maximum selectivity for a single target. In this review a multitarget drug survey was carried out as a promising strategy in several important diseases: neglected diseases, neurodegenerative diseases, AIDS, and cancer. In addition, we discuss Computer-Aided Drug Design (CADD) techniques as a tool in the projection of multitarget compounds against these diseases

Validation of Six Commercial Antibodies for the Detection of Heterologous and Endogenous TRPM8 Ion Channel Expression

TRPM8 is a non-selective cation channel expressed in primary sensory neurons and other tissues, including the prostate and urothelium. Its participation in different physiological and pathological processes such as thermoregulation, pain, itch, inflammation and cancer has been widely described, making it a promising target for therapeutic approaches. The detection and quantification of TRPM8 seems crucial for advancing the knowledge of the mechanisms underlying its role in these pathophysiological conditions. Antibody-based techniques are commonly used for protein detection and quantification, although their performance with many ion channels, including TRPM8, is suboptimal. Thus, the search for reliable antibodies is of utmost importance. In this study, we characterized the performance of six TRPM8 commercial antibodies in three immunodetection techniques: Western blot, immunocytochemistry and immunohistochemistry. Different outcomes were obtained for the tested antibodies; two of them proved to be successful in detecting TRPM8 in the three approaches while, in the conditions tested, the other four were acceptable only for specific techniques. Considering our results, we offer some insight into the usefulness of these antibodies for the detection of TRPM8 depending on the methodology of choice

Morphological and functional changes in TRPM8-expressing corneal cold thermoreceptor neurons during aging and their impact on tearing in mice

Morphological and functional alterations of peripheral somatosensory neurons during the aging process lead to a decline of somatosensory perception. Here, we analyze the changes occurring with aging in trigeminal ganglion (TG), TRPM8-expressing cold thermoreceptor neurons innervating the mouse cornea, which participate in the regulation of basal tearing and blinking and have been implicated in the pathogenesis of dry eye disease (DED). TG cell bodies and axonal branches were examined in a mouse line (TRPM8BAC-EYFP) expressing a fluorescent reporter. In 3 months old animals, about 50% of TG cold thermoreceptor neurons were intensely fluorescent, likely providing strongly fluorescent axons and complex corneal nerve terminals with ongoing activity at 348C and low-threshold, robust responses to cooling. The remaining TRPM81 corneal axons were weakly fluorescent with nonbeaded axons, sparsely ramified nerve terminals, and exhibited a low-firing rate at 348C, responding moderately to cooling pulses as do weakly fluorescent TG neurons. In aged (24 months) mice, the number of weakly fluorescent TG neurons was strikingly high while the morphology of TRPM81 corneal axons changed drastically; 89% were weakly fluorescent, unbranched, and often ending in the basal epithelium. Functionally, 72.5% of aged cold terminals responded as those of young animals, but 27.5% exhibited very low-background activity and abnormal responsiveness to cooling pulses. These morpho-functional changes develop in parallel with an enhancement of tear’s basal flow and osmolarity, suggesting that the aberrant sensory inflow to the brain from impaired peripheral cold thermoreceptors contributes to age-induced abnormal tearing and to the high incidence of DED in elderly people.This work was supported by grants FC-15-GRUPIN14–141 (Consejería de Economía y Empleo, Asturias, Spain),Fundación Ramón Areces, Caja Rural de Asturias, SAF2014–54518-C3-2-R, SAF2014– 54518-C3-1-R, SAF2017–83674-C2-2-R, SAF2017–83674-C2-1-R,SAF2016–77233-R (Ministerio de Economía, Industria y Competitividad, Spain and European Regional Development Funds, European Union)“Severo Ochoa” Program for Centers of Excellence in R&D (SEV-2013-0317)

PERFIL EPIDEMIOLÓGICO Y OBSTÉTRICO DE GESTANTES CON SÍNDROME HELLP

Estudio epidemiológico descriptivo cuya finalidad fue caracterizar las gestantes con Síndrome HELLP cuanto a los datos sociodemográficos y obstétricos y apuntar el número de casos de esa patología. La población fue constituida por 14 gestantes con diagnóstico de Síndrome HELLP, confirmado por exámenes laboratoriales y evaluación clínica, y atendidas en Unidad de Cuidados Intensivo en el periodo de enero de 2010 a diciembre de 2012. Los datos fueron obtenidos en 2013, con consulta a los prontuarios, utilizándose formulario con variables sociodemográficas y obstétricas. Los resultados evidenciaron que 64,3% de las gestantes tenían más de 26 años; 92,9% eran pardas; 64,3% no realizaron el prenatal; 78,6% no tenían historia de complicaciones en gestaciones anteriores. Los resultados apuntan datos semejantes a otros estudios sobre el perfil epidemiológico de la Síndrome HELLP y sirven de alerta sobre la carencia de informaciones en los prontuarios.Estudo epidemiológico descritivo objetivou caracterizar as gestantes com Síndrome HELLP quanto aos dados sociodemográficos e obstétricos e levantar o número de casos dessa patologia. A população foi constituída por 14 gestantes com diagnóstico de Síndrome HELLP, confirmado por exames laboratoriais e avaliação clínica, e atendidas em Unidade de Cuidados Intensivo no período de janeiro de 2010 a dezembro de 2012. A coleta de dados ocorreu em 2013, com consulta aos prontuários, utilizando-se formulário com variáveis sociodemográficas e obstétricas. Os resultados evidenciaram que 64,3% das gestantes tinham acima de 26 anos; 92,9% eram pardas; 64,3% não realizaram o pré-natal; 78,6% não tinham história de complicações em gestações anteriores. Os resultados apontam dados semelhantes a outros estudos sobre o perfil epidemiológico da Síndrome HELLP e servem de alerta sobre a carência de informações nos prontuários.This descriptive epidemiological study, with a quantitative approach, aimed to characterize the pregnant women with HELLP Syndrome regarding socio-demographic and obstetric data, and to ascertain the number of cases of this pathology. The population was constituted by 14 pregnant women diagnosed with HELLP Syndrome, confirmed by laboratory tests and clinical evaluation, and attended in an intensive care unit in the period January 2010 to December 2012. Data collection occurred in 2013, consulting the hospital records, using a form with socio-demographic and obstetric variables. The results evidenced that 64.3% of the pregnant women were aged over 26 years old; 92.9% were of mixed European, African and Indigenous ancestry; 64.3% did not undertake prenatal check-ups; and 78.6% had no history of complications in previous pregnancies. The results indicate data similar to that of other studies on the epidemiological profile of HELLP Syndrome, and serves as a warning regarding the shortage of information in the patient records.

Experiencias en la aplicación de tabletas en Secundaria

[ES] El objetivo de este trabajo consiste en presentar una serie de reflexiones sobre el uso de dispositivos tablet (tabletas) en el ámbito de la Enseñanza Secundaria. Este tipo de dispositivos viene utilizándose en diversos centros educativos repartidos por el estado español, principalmente en Educación Primaria, y pese a su potencial innovador y las ventajas tecnológicas que aportan, también aparecen dificultades cuando se busca una implantación efectiva de los mismos. Por un lado, en el trabajo se plantean ciertas cuestiones sobre el aprovechamiento didáctico de estos dispositivos y las necesidades o requisitos que ello implica. Por otra parte, se trata de extraer una serie de recomendaciones para una aplicación efectiva de este tipo de dispositivos. Para ello, se cuenta con la experiencia de un centro educativo a lo largo de varios cursos en la aplicación de tales tecnologías. A partir de dicha experiencia se analizan los resultados obtenidos y se pretende dar una nueva perspectiva en el uso didáctico de las tabletas.[EN] The aim of the current work is introducing some findings about the use of tablet devices in the context of Secondary Education. This kind of devices is used in many schools, all over the Spanish country, and particularly in Primary Education. In spite of their innovation potential and their technical contributions, some difficulties can be found to implement tabletbased scenarios in an effective way. On the one hand, the work deals with some issues about the didactical deployment of such devices together with their educational requirements. On the other hand, some recommendations are provided to support an effective use of these devices. In this sense, an experience about the application of this kind of technology within an educational institution throughout several courses is reported. From this experience, the gathered results are analyzed and a new perspective in the didactical use of tablets is depicted.Buendía García, F.; Benlloch-Dualde, J.; Zahonero Viana, I.; Cubel Barea, A. (2016). Experiencias en la aplicación de tabletas en Secundaria. Education in the Knowledge Society. 17(4):75-89. doi:10.14201/eks20161747589S758917