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

Dimensional stability of an addition silicone after disinfection/sterilization

Poster presented at the “From Basic Sciences to Clinical Research” – First International Congress of CiiEM. Egas Moniz, Caparica, Portugal, 27-28 November 2015"Dental impressions play a key role in clinical practice, and it is crucial to know the impact of disinfection or sterilization on it. The success of oral rehabilitation depends on the accuracy and reproducibility of the oral impressions [1,2,3]. The addition silicones and polyethers tend to be used most frequently for its physical and mechanical properties, such as dimensional stability [1,4,5].

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

POLÍTICA DE FORMAÇÃO DE PROFESSORES LEIGOS NA DITADURA CIVIL-MILITAR E A MEMÓRIA DE EDUCADORES NO SERTÃO DA BAHIA (1967 – 1983)

Resumo: Durante as décadas de 1960 a 1980, período de ditadura civil-militar no Brasil, foram criados programas de formação de professores com o objetivo de titular os chamados professores leigos. Um destes foi o “Programa de Aperfeiçoamento do Magistério Primário” – PAMP.  Este artigo apresenta algumas reflexões acerca das ações deste programa aplicadas em áreas rurais da cidade de Guanambi, localizada no semiárido baiano. Nossas fontes foram os documentos oficiais do referido programa, artigos acadêmicos escritos nos anos 1980 que trataram da análise da política de formação de professores leigos e depoimentos de cinco docentes que participaram de cursos promovidos pelo PAMP naquele período. Analisamos a estrutura organizativa desta política educacional em articulação à evocação das memórias das experiências das educadoras e educadores guanambienses estudados para tratar das divergências entre o proposto formalmente e o vivido por aqueles docentes

Uso do antifúngico miconazol como inibidor do crescimento de Blastocystis hominis em culturas de Entamoeba histolytica/E. dispar

In regions with high prevalence, Blastocystis hominis is frequently found in association with Entamoeba histolytica/E. dispar in xenic cultures. Its exacerbated growth is often superimposed on the growth of amebas, thus impeding the continuation of the amebas in the culture, within a few generations. The present study reports on the excellent efficacy (100%) of the antifungal agent miconazole in eliminating B. hominis from cultures of E. histolytica/E. dispar, thereby maintaining the integrity of the trophozoites of the amebas. Nystatin presented low efficacy (33.3%).Em regiões de alta prevalência, Blastocystis hominis é freqüentemente encontrado em associação com Entamoeba histolytica/E. dispar em cultivos xênicos. Seu crescimento exacerbado se sobrepõe muitas vezes ao das amebas, impedindo a manutenção destas em cultura, dentro de poucas gerações. O presente estudo relata a excelente eficácia (100%) do antifúngico miconazol na eliminação de B. hominis dos cultivos de E. histolytica/E. dispar, mantendo-se a integridade dos trofozoítos das amebas. A nistatina apresentou eficácia baixa (33,3%)

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