Luis Ulloa

ABSTRACT Resumen Abstract El presente artículo da cuenta de los The present article gives account of the main principales resultados de investigaciones results of developed experimental investigations experimentales desarrolladas en Chile con el in Chile that it has by objective to compare objetivo de comparar la estimación del tiempo the estimation of the time which adolescents que hacen adolescentes cuando se enfrentan do when they face the development of similar al desarrollo de tareas similares con o sin tasks with without computers. In addition pos-ordenadores. Además se analizan posibles sible cultural differences with groups of rural diferencias culturales con grupos de sujetos and urban subjects are analyzed. rurales y urbanos. The experience took place between the La experiencia tuvo lugar entre los meses months of April and May of the 2005 and the de abril y mayo de 2005 y los grupos de parti-groups of participants come from schools of the cipantes provienen de colegios de la provincia province of Valdivia in the south of Chile. de Valdivia en la zona sur de Chile. Key words: estimation of time, technological Palabras clave: estimación de tiempo, change, computers in the school, Chile, percep-cambio tecnológico, ordenadores en la escuela, tion of time, technology and culture. Chile, percepción de tiempo, tecnología y cultura.

The cholinergic anti-inflammatory pathway is a mechanism whereby local inflammation is modulated by the brain via the vagus nerve and nicotinic acetylcholine receptors (nAChRs). The nAChR family are ligand-gated ion channels that consist of many different subtypes formed by the specific assembly of five polypeptide subunits including alpha1-10, beta1-4, gamma, delta, and epsilon. The alpha7 receptor (alpha7nAChR) mediates the anti-inflammatory effects of cholinergic stimulation. We recently demonstrated that cholinergic agonists attenuate renal ischemia-reperfusion (I/R) injury in rats. We also showed that tubular epithelial cells express functional nAChRs in vitro. The current studies report the expression, localization, and regulation of the alpha7nAChR in the rat kidney after I/R injury. We also examined, in this model, potential interactions between cholinergic stimulation and the STAT3 pathway, a key signaling cascade that has been linked to alpha7nAChR activation. RT-PCR and immunohistochemistry showed constitutive expression of many nAChR subunits. Immunohistochemistry localized basal alpha7nAChR expression to the endothelium of cortical peritubular capillaries, and its distribution was upregulated after I/R injury. Western blotting also showed an increase in alpha7nAChR subunit protein after renal I/R injury. Interestingly, pretreatment with nicotine, which improves the outcome after renal I/R injury, reduced the alpha7nAChR protein after I/R injury. Finally, we found that I/R injury stimulated the STAT3 pathway, whereas pretreatment with nicotine downregulated its activation. These results suggest that the alpha7nAChR plays an important role in the pathophysiology of renal I/R injury.