RESUMEN
It is well known that exposure to fluorides lead to an increased ROS production and enhances the inflammatory reactions. Therefore we decided to examine whether cyclooxygenases (particular COX-2) activity and expression may be changed by fluoride in THP1 macrophages and in this way may change the prostanoids biosynthesis. In the present work we demonstrate that fluoride increased concentration of PGE2 and TXA2 in THP1 macrophages. Following exposure to 1-10 µM NaF, COX-2 protein and COX-2 transcript increased markedly. COX-2 protein up-regulation probably is mediated by ROS, produced during fluoride-induced inflammatory reactions. Additional fluoride activates the transcription factor, nuclear factor (NF)-kappaB, which is involved in the up-regulation of COX-2 gene expression. This study indicated that even in small concentrations fluoride changes the amounts and activity of COX-1 and COX-2 enzymes taking part in the initiating and development of inflammatory process.
Asunto(s)
Macrófagos/efectos de los fármacos , Monocitos/efectos de los fármacos , Fluoruro de Sodio/farmacología , Diferenciación Celular , Línea Celular , Ciclooxigenasa 1/genética , Ciclooxigenasa 2/genética , Ciclooxigenasa 2/metabolismo , Dinoprostona/metabolismo , Humanos , Inflamación/metabolismo , Macrófagos/metabolismo , Monocitos/metabolismo , Tromboxano A2/metabolismoRESUMEN
The speed and direction selectivity of responses of collicular neurons in pretrigeminal cats following lesions of the visual cortex were examined using moving light spots. Following cortical lesions the number of cells showing direction selectivity was reduced, but the number of cells showing speed selectivity was increased. It is suggested that some of the characteristics of collicular neurons are dependent on initial organization of the intracollicular synaptic connections rather than the corticocollicular ones.