Tauroursodeoxycholic acid attenuates neuronal apoptosis via the TGR5/ SIRT3 pathway after subarachnoid hemorrhage in rats

BACKGROUND: Neuronal apoptosis plays a critical event in the pathogenesis of early brain injury after subarachnoid hemorrhage (SAH). This study investigated the roles of Tauroursodeoxycholic acid (TUDCA) in attenuate neuronal apoptosis and underlying mechanisms after SAH. METHODS: Sprague-Dawley rats were subjected to model of SAH and TUDCA was administered via the internal carotid injection. Small interfering RNA (siRNA) for TGR5 were administered through intracerebroventricular injection 48 h before SAH. Neurological scores, brain water content, Western blot, TUNEL staining and immunofluorescence staining were evaluated. RESULTS: TUDCA alleviated brain water content and improved neurological scores at 24 h and 72 h after SAH. TUDCA administration prevented the reduction of SIRT3 and BCL-2 expressions, as well as the increase of BAX and cleaved caspase-3.Endogenous TGR5 expression were upregulated after SAH and treatment with TGR5 siRNA exacerbated neurological outcomes after SAH and the protective effects of TUDCA at 24 h after SAH were also abolished by TGR5 siRNA. CONCLUSIONS: Our findings demonstrate that TUDCA could attenuated neuronal apoptosis and improve neurological functions through TGR5/ SIRT3 signaling pathway after SAH. TUDCA may be an attractive candidate for anti-apoptosis treatment in SAH.

Association of taste receptor gene polymorphisms with dental caries

Abstract This study was performed to evaluate the interplay between dental caries, nutritional status, and genetic polymorphisms in TAS1R1 and TAS1R2 (taste receptor, type 1, member 1 and 2) in preschool children and pre-adolescents. We included 525 subjects (306 preschool children and 219 pre-adolescents). Parents/caregivers answered a self-administered questionnaire about their children's systemic health, characteristics, oral hygiene habits, and diet. Clinical examination was performed to evaluate dental caries and nutritional status. Saliva samples were collected for DNA extraction. The genotyping of rs17492553 ( TAS1R1 ), rs3935570, and rs4920566 ( TAS1R2 ) polymorphisms was performed using real-time PCR with Taqman Genotyping Master Mix and SNP assay. Both univariate and multivariate Poisson regression analyses with robust variance were used for the data analysis. In preschool children, consumption of sweets between meals increased the prevalence of dental caries by 85% (PR c = 1.85; 95%CI 1.39-2.46; p < 0.001), whereas in pre-adolescents, this prevalence increased by 34% (PR a = 1.34; 95%CI 1.11-1.62; p = 0.002), regardless of genetic polymorphisms . Moreover, individuals carrying at least one allele C in rs17492553 presented 23% more prevalence of dental caries (PR a = 1.23; 95%CI 1.02-1.49 p = 0.030). Nutritional status was not associated with dental caries, neither with genetic polymorphisms . Consumption of sweets between meals increased the prevalence of dental caries. In pre-adolescents, rs17492553 genetic polymorphism in TAS1R1 was associated with dental caries.

Effects of ICI 182, 780, an ERα and ERß antagonist, and G-1, a GPER agonist, on autophagy in breast cancer cells / Efeitos do antagonista seletivo do REα e do REß ICI 182, 780 e do agonista de GPER G-1 no processo de autofagia em células de câncer de mama

ABSTRACT Objective To investigate if ICI 182,780 (fulvestrant), a selective estrogen receptor alpha/beta (ERα/ERβ) antagonist, and G-1, a selective G-protein-coupled receptor (GPER) agonist, can potentially induce autophagy in breast cancer cell lines MCF-7 and SKBr3, and how G-1 affects cell viability. Methods Cell viability in MCF-7 and SKBr3 cells was assessed by the MTT assay. To investigate the autophagy flux, MCF-7 cells were transfected with GFP-LC3, a marker of autophagosomes, and analyzed by real-time fluorescence microscopy. MCF-7 and SKBr3 cells were incubated with acridine orange for staining of acidic vesicular organelles and analyzed by flow cytometry as an indicator of autophagy. Results Regarding cell viability in MCF-7 cells, ICI 182,780 and rapamycin, after 48 hours, led to decreased cell proliferation whereas G-1 did not change viability over the same period. The data showed that neither ICI 182,780 nor G-1 led to increased GFP-LC3 puncta in MCF-7 cells over the 4-hour observation period. The cytometry assay showed that ICI 182,780 led to a higher number of acidic vesicular organelles in MCF-7 cells. G-1, in turn, did not have this effect in any of the cell lines. In contrast, ICI 182,780 and G-1 did not decrease cell viability of SKBr3 cells or induce formation of acidic vesicular organelles, which corresponds to the final step of the autophagy process in this cell line. Conclusion The effect of ICI 182,780 on increasing acidic vesicular organelles in estrogen receptor-positive breast cancer cells appears to be associated with its inhibitory effect on estrogen receptors, and GPER does notseem to be involved. Understanding these mechanisms may guide further investigations of these receptors' involvement in cellular processes of breast cancer resistance.

RESUMO Objetivo Avaliar o efeito dos compostos ICI 182,780 (fulvestranto), um antagonista seletivo dos receptores de estrógeno alfa/beta (REα/REβ), e do G-1, um agonista seletivo de receptores de estrógeno acoplados a proteínas-G (GPER), na possível indução de autofagia em linhagens de câncer de mama MCF-7 e SKBr3, bem como o efeito de G-1 na viabilidade celular. Métodos A viabilidade celular de células MCF-7 e SKBr3 foi avaliada pelo ensaio com MTT. Para investigar a indução da autofagia, células MCF-7 foram transfectadas com GFP-LC3, um marcador de autofagossomos, e analisadas por microscopia de fluorescência em tempo real. As células MCF-7 e SKBr3 foram incubadas com o indicador de compartimentos ácidos laranja de acridina e analisadas por citometria de fluxo como indicativo para autofagia. Resultados Em células MCF-7, o ICI 182,780 e rapamicina após 48 horas levaram à diminuição da viabilidade celular, enquanto o G-1 não alterou a viabilidade no mesmo período de tratamento. Nem o ICI 182,780 e nem o G-1 induziram aumento na pontuação de GFP-LC3 em células MCF-7 até 4 horas. Já os ensaios de citometria de fluxo demonstraram que ICI 182,780 levou ao aumento de compartimentos ácidos em células MCF-7. O G-1 não aumentou estes parâmetros em ambas as linhagens. Por outro lado, ICI 182,780 e G-1 não induziram à redução da viabilidade em células SKBr3 e nem à formação de compartimentos ácidos, como etapa final do processo autofágico. Conclusão O aumento de compartimentos ácidos pelo ICI 182,780 em células de câncer de mama positivas para receptores de estrógeno parece estar associado com seu efeito inibidor de receptores de estrógeno, mas sem o envolvimento de GPER. A compreensão desses mecanismos pode direcionar estudos sobre o envolvimento dos receptores nos processos celulares de resistência do câncer de mama.

Palmitic acid-induced lipotoxicity promotes a novel interplay between Akt-mTOR, IRS-1, and FFAR1 signaling in pancreatic ß-cells

BACKGROUND: Free fatty acid receptor 1 (FFAR1) is G-protein coupled receptor predominantly expressed in pancreatic ß-cells that is activated by a variety of free fatty acids (FFAs). Once activated, it promotes glucose-stimulated insulin secretion (GSIS). However, increased levels of FFAs lead to lipotoxicity, inducing loss of ß-cell function. FFAR1 plays a key role in the development of type 2 diabetes (T2D), and previous studies have indicated the importance of developing anti-diabetic therapies against FFAR1, although its role in the regulation of ß-cell function remains unclear. The present study investigated the role of FFAR1 under lipotoxic conditions using palmitic acid (PA). The rat insulinoma 1 clone 832/13 (INS-1 832/13) cell line was used as a model as it physiologically resembles native pancreatic ß-cells. Key players of the insulin signaling pathway, such as mTOR, Akt, IRS-1, and the insulin receptor (INSR1ß), were selected as candidates to be analyzed under lipotoxic conditions. RESULTS: We revealed that PA-induced lipotoxicity affected GSIS in INS-1 cells and negatively modulated the activity of both IRS-1 and Akt. Reduced phosphorylation of both IRS-1 S636/639 and Akt S473 was observed, in addition to decreased expression of both INSR1ß and FFAR1. Moreover, transient knockdown of FFAR1 led to a reduction in IRS-1 mRNA expression and an increase in INSR1ß; mRNA. Finally, PA affected localization of FFAR1 from the cytoplasm to the perinucleus. CONCLUSIONS: In conclusion, our study suggests a novel regulatory involvement of FFAR1 in crosstalk with mTOR-Akt and IRS-1 signaling in ß-cells under lipotoxic conditions.

The tankyrase inhibitor G007-LK inhibits small intestine LGR5+ stem cell proliferation without altering tissue morphology

Abstract Background The WNT pathway regulates intestinal stem cells and is frequently disrupted in intestinal adenomas. The pathway contains several potential biotargets for interference, including the poly-ADP ribosyltransferase enzymes tankyrase1 and 2. LGR5 is a known WNT pathway target gene and marker of intestinal stem cells. The LGR5+ stem cells are located in the crypt base and capable of regenerating all intestinal epithelial cell lineages. Results We treated Lgr5-EGFP-Ires-CreERT2;R26R-Confetti mice with the tankyrase inhibitor G007-LK for up to 3 weeks to assess the effect on duodenal stem cell homeostasis and on the integrity of intestinal epithelium. At the administered doses, G007-LK treatment inhibited WNT signalling in LGR5+ stem cells and reduced the number and distribution of cells traced from duodenal LGR5+ stem cells. However, the gross morphology of the duodenum remained unaltered and G007-LK-treated mice showed no signs of weight loss or any other visible morphological changes. The inhibitory effect on LGR5+ stem cell proliferation was reversible. Conclusion We show that the tankyrase inhibitor G007-LK is well tolerated by the mice, although proliferation of the LGR5+ intestinal stem cells was inhibited. Our observations suggest the presence of a tankyrase inhibitor-resistant cell population in the duodenum, able to rescue tissue integrity in the presence of G007-LK-mediated inhibition of the WNT signalling dependent LGR5+ intestinal epithelial stem cells.

The search for novel insecticide targets in the post-genomics era, with a specific focus on G-protein coupled receptors

Insects are considered pests globally, implicated in the destruction of agricultural fields and transmission of pathogens that cause deadly human diseases, such as dengue, Zika and malaria. The diversity of the insecticide arsenal has remained stagnant for decades, but the recent rise of insecticide resistance fueled the discovery of novel modes of action, and the power of genomics has reinvigorated this search. This review discusses the importance of comparative and functional insect genomics in the identification of potential gene targets for an insecticidal mode of action with low off-target toxicity. Due to the global participation in the sequencing and annotation of insect genomes, the targeting of specific genes with molecular tools like RNAi and CRISPR/Cas9 for genome engineering and consequent functional identification and validation has become more efficient. While there are multiple avenues to explore for insecticidal candidates, this review identifies G-protein coupled receptors as attractive targets, and hones in on the octopamine and dopamine receptors due to their potential.

Nuevas terapias para la colestasis / New therapies in cholestasis

The introduction of ursodeoxycholic acid (UDCA) in the treatment of patients with cholestasis enabled remarkable progress and improvements in hepatic inflammatory activity, progression to cirrhosis and quality of life. However, the benefits of UDCA are particularly evident in patients with primary biliary cirrhosis and also 30 percent of patients have sub optimal response. For this reason, in order to improve the number of people with complete responses to therapy, new pharmacological alternatives have been investigated to add to UDCA treatment. This review aims to show potential new therapies against cholestasis that have been investigated by systematizing them depending on the receptor or target on which they act. Finally, a special reference will be made in relation to the treatment of pruritus associated with cholestasis.

La introducción del ácido ursodeoxicólico (AUDC) en el tratamiento de los pacientes con colestasia permitió notables avances con mejoras en la actividad inflamatoria hepática, progresión hacia la cirrosis y calidad de vida. Sin embargo, los beneficios de AUDC se aprecian especialmente en pacientes con cirrosis biliar primaria y además, 30 por ciento de los pacientes tiene una respuesta sub óptima. Por esta razón, con la finalidad de mejorar el número de personas con respuestas completas a la terapia, se han investigado nuevas alternativas farmacológicas para adicionar al tratamiento con AUDC. La presente revisión pretende mostrar las nuevas posibles terapias contra la colestasia estudiadas sistematizándolas según el tipo de receptor o diana sobre el que actúan. Finalmente se hará referencia especial en relación al tratamiento del prurito asociado a la colestasia.

Is there a relationship between complaints of impaired balance and postural control disorder in community-dwelling elderly women? A cross-sectional study with the use of posturography

Background: Risk of falls increases as age advances. Complaints of impaired balance are very common in the elderly age group. Objectives: The objective of this study was to investigate whether the subjective perception of impaired balance was associated with deficits in postural control (objective analysis) in elderly community-dwelling women. Method: Static posturography was used in two groups: elderly women with (WC group) and without (NC group) complaints of impaired balance. The area, mean sway amplitude and mean speed of the center of pressure (COP) in the anterior-posterior (AP) and medial-lateral (ML) directions were analyzed in three stances: single-leg stance, double-leg stance and tandem stance, with eyes open or closed on two different surfaces: stable (firm) and unstable (foam). A digital chronometer was activated to measure the time limit (Tlimit) in the single-leg stance. Kruskal-Wallis tests followed by Mann-Whitney tests, Friedman analyses followed by post hoc Wilcoxon tests and Bonferroni corrections, and Spearman statistical tests were used in the data analysis. Differences of p<0.05 were considered statistically significant. Results: The results of posturography variables revealed no differences between groups. The timed single-leg stance test revealed a shorter Tlimit in the left single-leg stance (p=0.01) in WC group compared to NC group. A negative correlation between posturography variables and Tlimit was detected. Conclusions: Posturography did not show any differences between the groups; however, the timed single-leg stance allowed the authors to observe differences in postural control performance between elderly women with and those without complaints of impaired balance. .

Anthropometric indicators of obesity in the prediction of high body fat in adolescents / Indicadores antropométricos de obesidade na predição de gordura corporal elevada em adolescentes

OBJECTIVE: To determine the anthropometric indicators of obesity in the prediction of high body fat in adolescents from a Brazilian State. METHODS: The study included 1,197 adolescents (15-17 years old). The following anthropometric measurements were collected: body mass (weight and height), waist circumference and skinfolds (triceps and medial calf). The anthropometric indicators analyzed were: body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR) and conicity index (C-Index). Body fat percentage, estimated by the Slaughter et al equation, was used as the reference method. Descriptive statistics, U Mann-Whitney test, and ROC curve were used for data analysis. RESULTS: Of the four anthropometric indicators studied, BMI, WHtR and WC had the largest areas under the ROC curve in relation to relative high body fat in both genders. The cutoffs for boys and girls, respectively, associated with high body fat were BMI 22.7 and 20.1kg/m², WHtR 0.43 and 0.41, WC 75.7 and 67.7cm and C-Index 1.12 and 1.06. CONCLUSIONS: Anthropometric indicators can be used in screening for identification of body fat in adolescents, because they are simple, have low cost and are non-invasive. .

OBJETIVO: Determinar os indicadores antropométricos de obesidade na predição da gordura corporal elevada em adolescentes de um estado brasileiro. MÉTODOS: O estudo incluiu 1.197 adolescentes (15-17 anos). As seguintes medidas antropométricas foram coletadas: massa corporal e estatura, perímetro da cintura e dobras cutâneas (tríceps e perna medial). Os indicadores antropométricos analisados foram: índice de massa corporal (IMC), perímetro da cintura (PC), razão cintura-estatura (RCE) e índice de conicidade (IC). A gordura corporal elevada, estimada pela equação de Slaughter et al., foi usada como método de referência. Estatística descritiva, teste U de Mann-Whitney e curva ROC foram usadas para a análise dos dados. RESULTADOS: Dos quatro indicadores antropométricos estudados, o IMC, a RCE e o PC tiveram as maiores áreas sob a curva ROC em relação à gordura corporal elevada relativa em ambos os sexos. Os pontos de corte para os rapazes e as moças, respectivamente, associados com gordura corporal elevada foram IMC 22,7 e 20,1 kg/m2, RCE 0,43 e 0,41, PC 75,7 e 67,7 cm e IC 1,12 e 1,06. CONCLUSÕES: Os indicadores antropométricos podem ser usados como ferramenta para identificação da gordura corporal em adolescentes, por serem um método simples, de baixo custo e não invasivo. .

A atividade do NHE3 em túbulo proximal é inibida pela sinalização enviesada do receptor de angiotensina II tipo 1/beta-arrestina / Proximal tubule NHE3 activity is inhibited by beta-arrestin-biased angiotensin II type 1 receptor signaling

Os receptores medeiam a maioria das respostas fisiológicas em resposta a diversidade de estímulos. A ativação da sinalização mediada pelo receptor de angiotensina II tipo 1 é o principal responsável pelos efeitos do hormônio angiotensina II (Ang II) nos tecidos alvo. No rim concentrações fisiológicas de Ang II aumentam a atividade no túbulo proximal da isoforma 3 do trocador de Na+/H+ (NHE3). Este efeito é crucial para a manutenção do volume extracelular e pressão arterial. Evidências recentes mostraram que a ativação seletiva da sinalização enviesada da beta-arrestina/ receptor AT1 induz diurese e natriurese independentemente da sinalização via proteína G. Neste estudo testamos a hipótese de que a sinalização enviesada do receptor AT1/ beta-arrestina inibe a atividade do NHE3 no túbulo proximal, bem como investigar os possíveis mecanismos moleculares que medeio este efeito. Para tal, nós determinamos os efeitos do composto TRV120023, que se liga ao receptor AT1, bloqueando o acoplamento da proteína G e estimulando a sinalização da beta-arrestina, na função do NHE3 in vivo e in vitro. A atividade do NHE3 foi medida quer em túbulo proximal nativo, por meio de microperfusão estacionária, bem como em uma linha celular de túbulo proximal de gamba (OKP), por meio de recuperação de pH intracelular dependente de Na+. Os nossos resultados mostram que o TRV120023 na concentração de 10-7 M inibe marcadamente a atividade do NHE3 em túbulo proximal quer in vivo quer in vitro, sendo que este efeito é completamente abolido nas células silenciadas para a beta-arrestina 1 e 2 através de RNA de interferência. Adicionalmente, a estimulação do NHE3 pela Ang II é completamente suprimida pelo TRV120023 quer in vivo quer in vitro. A inibição do NHE3 pelo TRV120023 foi associada com a diminuição do NHE3 expresso na superfície da membrana plasmática em células OKP e com a redistribuição entre o corpo e a base das microvilosidades em túbulo proximal de rato. A...

Cell surface receptors mediate most of our physiological responses to an array of stimulus. The triggering of the angiotensin II type I (AT1) receptor signaling is the major control point in the regulation of the ultimate effects of the peptide hormone angiotensin II (Ang II) on its target tissue. In the kidney physiological concentrations of Ang II upregulate the activity of proximal tubule Na+/H+ exchanger isoform 3 (NHE3). This effect is crucial for maintenance of extracellular fluid volume homeostasis and blood pressure. Recent findings have shown that selective activation of the betaarrestin-biased AT1 receptor signalingpathway induces diuresis and natriuresis independent of G-protein mediated signaling. This study tested the hypothesis that activation of this AT1 receptor/beta-arrestin signaling inhibits NHE3 activity in proximal tubule as well as investigate the underlying molecular mechanisms mediating this effect. To this end, we determined the effects of the compound TRV120023, which binds to the AT1R, blocks G protein coupling, and stimulates beta-arrestin signaling, on NHE3 function in vivo and in vitro. NHE3 activity was measured in both native proximal tubules, by stationary microperfusion, and in opossum proximal tubule (OKP) cells, by Na+-dependent intracellular pH recovery. Our results showed that 10-7 MTRV120023 remarkably inhibited proximal tubule NHE3 activity both in vivo and in vitro, and the effect was completely abolished in OKP cells silenced for beta-arrestin 1 and 2 by small interference RNA. Additionally, stimulation of NHE3 by Ang II was completely suppressed by TRV120023 both in vivo as well as in vitro. Inhibition of NHE3 activity by TRV120023 was associated with a decrease in NHE3 surface expression in OKP cells and with a redistribution from the body to the base of the microvilli in the rat proximal tubule. The decreased surface NHE3 in OKP cells was associated with an increase in NHE3 internalization via...

Disfunção autonômica e anticorpos contra receptores anti-m2 e anti-β1 em pacientes chagásicos / Autonomic dysfunction and anti-M2 and anti-β1 receptor antibodies in Chagas disease patients

FUNDAMENTO: A morte súbita é a principal causa de óbito na doença de Chagas, acometendo pacientes mesmo em fases precoces da doença. É reconhecido o comprometimento do sistema nervoso autônomo nessa doença e seu potencial como deflagrador de arritmias malignas quando associado a alterações estruturais ou metabólicas. OBJETIVO: Buscamos identificar, em pacientes chagásicos com função sistólica preservada, o comprometimento do sistema nervoso autônomo e sua associação com anticorpos funcionalmente ativos contra receptores anti-m2 e anti-β1. MÉTODOS: Mediante análise espectral da variabilidade RR durante teste de inclinação passiva, pacientes chagásicos crônicos foram comparados com controles saudáveis pareados por idade. Posteriormente, a associação de disfunção autonômica com anticorpos funcionalmente ativos com ação anti-m2 e anti-β1 foi pesquisada pelo método de Langendorf. RESULTADOS: Observamos que pacientes chagásicos sem disfunção ventricular expressam atividade parassimpática ante um estímulo vagal, porém com menor intensidade em relação aos controles. Pacientes chagásicos com anticorpos anti-m2 ou anti-β1 apresentaram uma redução ainda mais expressiva da resposta vagal durante a arritmia sinusal respiratória, independentemente da presença de lesão estrutural. Entretanto, a associação de ambos promoveu resposta ao estímulo vagal similar aos chagásicos sem a presença dos mesmos. CONCLUSÃO: A menor reserva vagal em pacientes chagásicos com função preservada esteve associada à presença de anticorpos anti-m2 ou anti-β1 funcionalmente ativos, e não à presença de lesão cardíaca estrutural.

BACKGROUND: Sudden death is the leading cause of death in Chagas' disease, affecting patients even in the early stages of the disease. The impairment of the autonomic nervous system in this disease has been recognized, as well as its potential as a trigger for malignant arrhythmias when associated with structural or metabolic changes. OBJECTIVE: We sought to identify, in Chagas patients with preserved systolic function, the impairment of the autonomic nervous system and its association with functionally active anti-m2 and anti-β1 receptor antibodies. METHODS: Using spectral analysis of RR variability during passive tilt test, chronic chagasic patients were compared with healthy controls matched for age. Subsequently, the association of autonomic dysfunction with functionally active antibodies with anti-m2 and anti-β1 action was investigated by the Langendorf method. RESULTS: We observed that patients with Chagas disease without ventricular dysfunction express parasympathetic activity against a vagal stimulus, however with less intensity compared to controls. Chagasic patients with anti-m2 or anti-β1 antibodies showed a further significant reduction of the vagal response during respiratory sinus arrhythmia, regardless of the presence of structural lesion. However, the association of both factors promoted response to vagal stimulation similar to that seen in Chagas disease without their presence. CONCLUSION: The lower vagal reserve in Chagas patients with preserved function was associated with functionally active anti-m2 or anti-β1 antibodies, and not with the presence of structural heart lesion.

Search for a platelet-activating factor receptor in the Trypanosoma cruzi proteome: a potential target for Chagas disease chemotherapy

Chagas disease (CD) causes the highest burden of parasitic diseases in the Western Hemisphere and is therefore a priority for drug research and development. Platelet-activating factor (PAF) causes the CD parasite Trypanosoma cruzi to differentiate, which suggests that the parasite may express PAF receptors. Here, we explored the T. cruzi proteome for PAF receptor-like proteins. From a total of 23,000 protein sequences, we identified 29 hypothetical proteins that are predicted to have seven transmembrane domains (TMDs), which is the main characteristic of the G protein-coupled receptors (GPCRs), including the PAF receptor. The TMDs of these sequences were independently aligned with domains from 25 animal PAF receptors and the sequences were analysed for conserved residues. The conservation score mean values for the TMDs of the hypothetical proteins ranged from 31.7-44.1 percent, which suggests that if the putative T. cruzi PAF receptor is among the sequences identified, the TMDs are not highly conserved. These results suggest that T. cruzi contains several GPCR-like proteins and that one of these GPCRs may be a PAF receptor. Future studies may further validate the PAF receptor as a target for CD chemotherapy.

El sentido del gusto / The sense of taste

El gusto es un sistema sensorial complejo que está vinculado a las conductas alimenticias del ser humano. Interactúa con el olfato, la sensibilidad táctil y térmica oral, y hasta con la visión y la audición. Se describen actualmente cinco variedades de gusto: dulce, salado, ácido, amargo y umami. Los receptores gustativos se encuentran fundamentalmente en la boca. En la transducción del estímulo gustativo participan dos mecanismos: canales iónicos para los gustos salado y ácido y receptores de membrana asociados a proteínas G para los restantes tres sabores. Se describe la vía gustativa y sus conexiones con el sistema límbicovinculadas con el placer-displacer de la gustación (hedonismo). Existen avances importantes relacionados con la codificación de los distintos estímulos gustativos, siendo la propuesta más fundamentada y aceptada la teoría de los ®patrones de actividad central¼. Algunos reflejos gustativos se producen al servicio de la masticación, por ejemplo los reflejos gustativos salivales para la formación del bolo, gustativo motor para la modulación de la frecuencia masticatoria y gustativo facial para comia y para laexpresión hedónica.

The sense of taste is a complex sensorial system related to the human feeding behavior. It interacts with the senses of smell, vision, audition and oral touch. Currently, five taste modalities are recognized: sweet, salty, sour, bitter and umami. Taste receptors are located mostly in the mouth. Two mechanisms are involved in the stimulus transduction in taste: ionic channels in the salty and sour tastes, and receptors associated to G-proteins in the transduction of the other three tastes. We describe thegustative neural pathway and their connections with the limbic system, related with the hedonic components of taste. We describe the theories advanced to explain the codification of the gustatory stimulus, with the ®central pattern activity¼ being the most accepted nowadays. Some taste reflexes have an accesory function in mastication, for example, the taste-salivary reflex helps in bolus formation, the taste-motor reflex regulates the masticatory frequency, and the gustofacial reflex helps with themastication and expresses the hedonic state.

Receptor acoplado a proteína G familia C6A: Posible blanco molecular en hueso / G Protein-Coupled Receptor Family C 6A (GPRC6A): Possible molecular target in Bone

El GPRC6A es un miembro recientemente identificado de la familia C de receptores acoplados a proteínas G (GPCRs) que está estrechamente emparentado con el receptor sensor de calcio (CASR). Se ha demostrado que este receptor es capaz de sensar cationes extracelulares y aminoácidos y que requiere tanto de los cationes extracelulares y de los aminoácidos para su óptima estimulación in vitro. El estudio del perfil de ligandos ha mostrado que la l-ornithine es el más potente eficaz l-aminoácido agonista seguido de varios otros aminoácidos alifáticos, neutros, y básicos. Algunos estudios han mostrado la activación por cationes del GPRC6A, pero comparado con el CASR, se necesitan concentraciones extracelulares más altas de calcio para activar este receptor. Es más, el Mg(2+) ha mostrado ser un modulador positivo de la respuesta a la l-ornithine. Se lo ha propuesto como el candidato para el elusivo mecanismo de sensado de calcio extracelular del osteoblasto, que se sabe responde a altas concentraciones locales de Ca²+. También se ha propuesto al GPRC6A como candidato a receptor de la osteocalcina, regulando el metabolismo energético y como blanco molecular para la acción del estroncio sobre el hueso.

GPRC6A is a recently identified member of family C of G protein-coupled receptors (GPCRs) that is closely related to the calcium-sensing receptor CASR. It has recently been shown that GPRC6A extracellular cations and amino acids and requires both extracellular cations and amino acids for optimal stimulation in vitro. The study of the ligand profile of GPRC6A has shown that l-ornithine is the most potent and efficacious l-amino acid agonist, followed by several other aliphatic, neutral, and basic amino acids. Some studies show cation-dependent activation of GPRC6A, but compared to CASR, much higher extracellular calcium concentrations are needed to activate this receptor. Furthermore, the divalent cation Mg(2+) was found to be a positive modulator of the l-ornithine response. GPRC6A may be a candidate for the elusive extracellular calcium-sensing mechanism known to be present in osteoblasts, which respond to high local Ca²+ concentrations. GPRC6A has also been proposed as a candidate receptor for ostocalcin, regulating energy metabolism and as a molecular target for the action of strontium on bone.

Sensopercepción gustativa: una revisión / Gustatory sensory perception: a review

Los órganos de los sentidos confieren a los seres humanos la capacidad de percibir y responder a una gran gama de estímulos que provienen del entorno, lo cual nos brinda la facultad de elaborar respuestas con el fin de adaptarnos a los cambios medioambientales, cubrir nuestras necesidades básicas y sobrevivir. Para nutrirnos, el sentido del gusto posee un rol primordial que nos permite seleccionar dentro de una amplia variedad de alimentos, las sustancias que son necesarias para nuestro metabolismo, protegiéndonos a su vez de compuestos potencialmente nocivos, debido a su toxicidad o grado de descomposición. Este sentido también es capaz de brindarnos la capacidad de seleccionar y discriminar alimentos que nos permitan sentir agrado y placer. Para los dentistas es fundamental comprender adecuadamente los complejos procesos del sentido del Gusto, identificar las estructuras involucradas tanto a nivel periférico (papilas, receptores y vías nerviosas) como a nivel central (núcleos y cortezas cerebrales); además de conocer las modalidades básicas del gusto y sus respectivos mecanismos de transducción. Este conocimiento aportará los elementos necesarios para enfrentar de manera correcta una situación en la cual un paciente presente una alteración gustativa, siendo capaz de identificar las posibles causas y adoptar medidas adecuadas para resolverla y/o tolerarla en el caso de ser provocada en forma transitoria por un procedimiento que forme parte o no de nuestro tratamiento.

The sense organs give to humans the ability to perceive and respond to a wide range of stimuli from the environment. This allows us the power to shape responses in order to adapt to environmental changes, control our basic needs and survive. The sense of taste has a key role in nurture. Enable us to select from a wide variety of foods, elements that are necessary for metabolism and also protecting from potentially harmful compounds, as of its toxicity or degree of decomposition. This sense of taste is also capable of giving us the ability to select and discriminate food that allow us to feel enjoy and pleasure. For dentists is critical to understand adequately the complex processes of taste, identify the structures involved peripheral (papillae, nerve pathways and receptors) and central (nuclei and cerebral cortices), besides knowing the basic modalities of taste and their respective transduction mechanisms. This knowledge will provide the basis to address properly a situation in which a patient has an altered taste, being able to identify possible causes and take appropriate action to resolve it and / or tolerate if temporary caused by a procedure that may be part of our dental treatment.

Expression and function of G-protein-coupled receptorsin the male reproductive tract

This review focuses on the expression and function of muscarinic acetylcholine receptors (mAChRs), α1-adrenoceptors and relaxin receptors in the male reproductive tract. The localization and differential expression of mAChR and α1-adrenoceptor subtypes in specific compartments of the efferent ductules, epididymis, vas deferens, seminal vesicle and prostate of various species indicate a role for these receptors in the modulation of luminal fluid composition and smooth muscle contraction, including effects on male fertility. Furthermore, the activation of mAChRs induces transactivation of the epidermal growth factor receptor (EGFR) and the Sertoli cell proliferation. The relaxin receptors are present in the testis, RXFP1 in elongated spermatids and Sertoli cells from rat, and RXFP2 in Leydig and germ cells from rat and human, suggesting a role for these receptors in the spermatogenic process. The localization of both receptors in the apical portion of epithelial cells and smooth muscle layers of the vas deferens suggests an involvement of these receptors in the contraction and regulation of secretion.

Esta revisão enfatiza a expressão e a função dos receptores muscarínicos, adrenoceptores α1 e receptores para relaxina no sistema reprodutor masculino. A expressão dos receptores muscarínicos e adrenoceptores α1 em compartimentos específicos de dúctulos eferentes, epidídimo, ductos deferentes, vesícula seminal e próstata de várias espécies indica o envolvimento destes receptores na modulação da composição do fluido luminal e na contração do músculo liso, incluindo efeitos na fertilidade masculina. Além disso, a ativação dos receptores muscarínicos leva à transativação do receptor para o fator crescimento epidermal e proliferação das células de Sertoli. Os receptores para relaxina estão presentes no testículo, RXFP1 nas espermátides alongadas e células de Sertoli de rato e RXFP2 nas células de Leydig e germinativas de ratos e humano, sugerindo o envolvimento destes receptores no processo espermatogênico. A localização de ambos os receptores na porção apical das células epiteliais e no músculo liso dos ductos deferentes de rato sugere um papel na contração e na regulação da secreção.

Family A G-Protein coupled receptors: an overview of structure-function relationships

Family A G-protein coupled receptors (AGPCRs) form the largest group of correlate receptors whose structure, a bundle of seven-trans-membrane (7 TM) helices, may be activated thus becoming able to transduce a signal from the extracellular medium to the cytosol. This activation may be constitutional, for instance due to permanent structural modifications, or be physiologically triggered by agonist binding at an external and accessible specific site. Based on thestructures of agonists, AGPCRs may be divided according to pharmacological assays into many classes of receptors, each one comprising many types or sub-types of proteins, as differentiated by specific binding of inhibitors, all of them performing a multitude of functions. It is noteworthy that AGPCRs have been more recently cloned and their sequences of amino acids determined in a large scale, a condition that has allowed these receptors to be sorted by a new criterium. Sequence analyses have consistently matched functional assays for classification of AGPCRs except for a certain number of functionally unknown receptors which have been cataloged as orphan receptors. A colossal number of AGPCRs, more than 10,000 sequences belonging to more than 1,000 different types of receptors, may nowadays be multiply-aligned what has been enabling the determination of parameters of residue conservation and characterization of special motifs along the structure of these proteins. There are at the present time, high-resolution 3D structures for the following AGPCRs: inactive rhodopsin, retinal-free opsin, Beta adrenoceptor and adenosine receptors. Among them, hodopsin structures are reliable enough to be used as prototypes for analyses of residue conservation and mechanisms of activation of receptors, specially at the level of the more conserved structure in the cytosolic half of their 7TM bundle.

New approaches for G-protein coupled receptor ligands identification

G protein-coupled receptors (GPCRs) represent the class of proteins with the highest impact from social, therapeutic and economic point of view. Today, more than 50% of drug targets are based on GPCRs and the annual worldwide sales exceeds 50 billion dollars. GPCRs are involved in all major diseases areas such as cardiovascular, metabolic, neurodegenerative, psychiatric, cancer and infectious diseases. The classical drug discovery process has relied on screening compounds, which interact favorably with the GPCR of interest followed by further chemical engineering as a mean of improving efficacy and selectivity. On the other hand, several new peptides with potential bioactivity are discovery every year. This review will focus on recent advancement on methods for identification of novel peptides with potential ability to activate GPCRs.

O sistema apelinérgico: papel na fisiologia e patologia humanas e potenciais aplicações terapêuticas / The apelinergic system: the role played in human physiology and pathology and potential therapeutic applications

A apelina é um peptídeo recentemente descoberto e identificado como o ligando endógeno do receptor APJ. A apelina e o receptor APJ são expressos numa grande variedade de tecidos, tais como coração, cérebro, rins e pulmões, onde a sua interação pode ter importantes efeitos fisiopatológicos. Com efeito, a última década foi fértil no esclarecimento de possíveis papéis desempenhados pela apelina na fisiologia humana, nomeadamente como peptídeo regulador dos sistemas cardiovascular, hipotálamo-hipófisário, gastrointestinal e imunitário. Um possível envolvimento da apelina na patogênese de doenças com elevada prevalência e co-morbilidades, como a hipertensão arterial, a insuficiência cardíaca e o diabete melito tipo 2, perspectivam-na como um possível alvo terapêutico a explorar no futuro. Este trabalho fornece uma visão geral dos efeitos fisiológicos da apelina e apresenta o possível papel desse peptídeo na patogênese de várias doenças, associado a implicações terapêuticas que poderão vir a ser, assim, exploradas.

Apelin is a recently discovered peptide, identified as an endogenous ligand of receptor APJ. Apelin and receptor APJ are expressed in a wide variety of tissues including heart, brain, kidneys and lungs. Their interaction may have relevant pathophysiologic effects in those tissues. In fact, the last decade has been rich in illustrating the possible roles played by apelin in human physiology, namely as a regulating peptide of cardiovascular, hypothalamus-hypophysis, gastrointestinal, and immune systems. The possible involvement of apelin in the pathogenesis of high prevalence conditions and comorbidities - such as hypertension, heart failure, and Diabetes Mellitus Type 2 (T2DM) - rank it as a likely therapeutic target to be investigated in the future. The present paper is an overview of apelin physiologic effects and presents the possible role played by this peptide in the pathogenesis of a number of conditions as well as the therapeutic implications that might, therefore, be investigated.