RESUMO
We previously reported that mouse parotid acinar cells display anion conductance (I(ATPCl)) when stimulated by external ATP in Na+-free extracellular solutions. It has been suggested that the P2X7 receptor channel (P2X7R) might underlie I(ATPCl). In this work we show that I (ATPCl) can be activated by ATP, ADP, AMP-PNP, ATPgammaS and CTP. This is consistent with the nucleotide sensitivity of P2X7R. Accordingly, acinar cells isolated from P2X7R( -/- ) mice lacked I(ATPCl). Experiments with P2X7R heterologously expressed resulted in ATP-activated currents (I(ATP-P2X7)) partially carried by anions. In Na(+)-free solutions, I (ATP-P2X7) had an apparent anion permeability sequence of SCN(-) > I(-) congruent with NO3(-) > Br(-) > Cl(-) > acetate, comparable to that reported for I(ATPCl) under the same conditions. However, in the presence of physiologically relevant concentrations of external Na+, the Cl(-) permeability of I(ATP-P2X7) was negligible, although permeation of Br(-) or SCN(-) was clearly resolved. Relative anion permeabilities were not modified by addition of 1 mM: carbenoxolone, a blocker of Pannexin-1. Moreover, cibacron blue 3GA, which blocks the Na(+) current activated by ATP in acinar cells but not I(ATPCl), blocked I(ATP-P2X7) in a dose-dependent manner when Na+ was present but failed to do so in tetraethylammonium containing solutions. Thus, our data indicate that P2X7R is fundamental for I(ATPCl) generation in acinar cells and that external Na+ modulates ion permeability and conductivity, as well as drug affinity, in P2X7R.
Assuntos
Ânions/metabolismo , Glândula Parótida/fisiologia , Receptores Purinérgicos P2/fisiologia , Sódio/fisiologia , Nucleotídeos de Adenina/farmacologia , Trifosfato de Adenosina/fisiologia , Animais , Linhagem Celular , Humanos , Camundongos , Glândula Parótida/citologia , Glândula Parótida/efeitos dos fármacos , Permeabilidade/efeitos dos fármacos , Receptores Purinérgicos P2/efeitos dos fármacos , Receptores Purinérgicos P2X7 , Triazinas/farmacologiaRESUMO
BACKGROUND: Variability in salivary proteins and their posttranslational modifications may play an important role in determining their protective features against dental caries. Knowledge of molecular content of saliva in different populations is important for a better understanding of protective properties of this biological fluid. Aims of this study were to analyze electrophoretic pattern and protein composition in resting human whole saliva (HWS) of a Mexican population and to correlate these data with decayed, missing, and filled teeth (DMFT) index in these subjects. METHODS: Resting human whole saliva samples were collected from 120 healthy Mexican dental students. Salivary flow rate, protein concentration, and electrophoretic profile analyzed qualitatively by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were correlated with DMFT index. Gels were successively triple-stained with Coomassie brilliant blue R250, periodic acid Schiff (PAS), silver stain, and salivary molecules were scored as absent (-), present (+/-), and high intensity and size (+). RESULTS: These showed no substantial differences in number of bands between males and females; however, a slight correlation between total protein concentration and sex was found (p Assuntos
Cárie Dentária/diagnóstico
, Saliva/metabolismo
, Adolescente
, Adulto
, Cárie Dentária/epidemiologia
, Eletroforese em Gel de Poliacrilamida
, Feminino
, Glicoproteínas/genética
, Humanos
, Masculino
, México
, Mucina-5B
, Mucinas/biossíntese
, Mucinas/genética
, Peptídeos/genética
, Peptídeos/metabolismo
, Fenótipo
, Polimorfismo Genético
, Domínios Proteicos Ricos em Prolina
, Proteínas e Peptídeos Salivares/biossíntese
, Proteínas e Peptídeos Salivares/genética
, Fatores Sexuais
RESUMO
Objetivo. Determinar los promedios de flujo salival y la concentración de proteínas totales en una población joven del Estado de México. Material y métodos. Se seleccionaron 120 sujetos a quienes se les colectó saliva total humana(STH) no estimulada y estimulada, la cual se analizó por medio de gravimetría y espectrofotometría (LV/LU); se calcularon medidas de tendencia central y de dispersión; posteriormente, se correlacionaron estos datos con los índices CPOD y CPITN. Resultados. Los sujetos estudiados mostraron un promedio en la concentración de proteínas (mg/min ñ DE) en STH no estimulada de 0.397 ñ .26, y en STH estimulada, de 0.973 ñ .53. El promedio en la concentración de proteínas (mg/ml ñ DE) fue de 1.374 ñ .45 en STH no estimulada y de 1.526 ñ .44 en STH estimulada. Las mujeres presentaron un menor porcentaje de flujo salival y mayor concentración de proteínas. No se observaron correlaciones entre el flujo y la concentración de proteínas totales y el CPOD y CPITN; sin embargo, sí las hubo con otras variables. Conclusiones. Estos hallazgos podrían estar asociados con el grado de nutrición, las características genéticas y los niveles de salud bucal en nuestra población. El presente estudio representa la fase inicial de la creación de una base de datos en sialoquímica, cuya meta será identificar los parámetros que indiquen el riesgo de enfermedades sistémicas o bucodentales
Objective. To determine the average salivary flow rates and total protein concentrations in a population of the State of Mexico. Material and methods. A gravimetric and spectrophotometric analysis was applied to 120 subjects in total resting and stimulated whole saliva and results were correlated with the DMFT and CPITN indexes. Results. Subjects allowed average salivary flow rate (ml/min ± SD) in non-stimulated human whole saliva (HWS) of 0.397±.26 and in stimulate d HWS of 0.973±.53. Average protein concentration was (mg/ml ± SD) 1.374±.45 in non-stimulated HWS and 1.526±.44 in stimulated HWS. Females showed a lower percentage of salivary flow and greater protein concentrations. No correlations were observed between flow and total protein concentration, and DMFT and CPITN; however, correlations were present with other variables. Conclusions. These findings could be associated to degree of nutrition, genetic characteristics and level of oral disease in our population. Present results represent the first step to create a database in sialochemistry to identify risk indicators of specific oral and systemic diseases.