O óxido nítrico (NO) no controle neural da pressão arterial: Modulação da transmissão glutamatérgica no NTS

The neuromodulatory effect of nitric oxide (NO) on glutamatergic transmission within the NTS related to cardiovascular regulation has been widely investigated. Activation of glutamatergic receptors in the NTS stimulates the production and release of NO and other nitrosyl substances with neurotransmitter/neuromodulator properties. The presence of NOS, including the protein nNOS and its mRNA in vagal afferent terminals in the NTS and nodose ganglion cells suggest that NO can act on glutamatergic transmission. We previously reported that iontophoresis of L-NAME on NTS neurons receiving vagal afferent inputs significantly decreased the number of action potentials evoked by iontophoretic application of AMPA. In addition, iontophoresis of the NO donor papaNONOate enhanced spontaneous discharge and the number of action potentials elicited by AMPA, suggesting that NO could be facilitating AMPA-mediated neuronal transmission within the NTS. Furthermore, the changes in renal sympathetic discharge during activation of baroreceptors and cardiopulmonary receptors involve activation of AMPA and NMDA receptors in the NTS and these responses are attenuated by microinjection of L-NAME in the NTS of conscious and anesthetized rats. Cardiovascular responses elicited by application of NO in the NTS are closely similar to those obtained after activation of vagal afferent inputs, and L-glutamate is the main neurotransmitter of vagal afferent fibers. In this review we discuss the possible neuromodulatory mechanisms of central produced/released NO on glutamatergic transmission within the NTS.

Screen-printed carbon electrode modified with poly-L-histidine applied to voltammetric determination of chromium (VI)

The present work reports the use of a screen-printed carbon electrode (SPCE) modified by poly-L-histidine film to determine chromium (VI). Stable films can be formed by direct addition of PH solution 1 % (w/v) on the electrode surface, followed by heating at 80°C during 5 min. Calibration curves can be constructed for Cr(VI) from 1.0 × 10-5 mol L-1 to 7.0 × 10-5 mol L-1 Cr (VI) in acetate buffer pH 4 using a preconcentration step of 60s at open circuit potential. A relative standard deviation of 3.2% was for five determination of 4.0 × 10 -5 mol L-1 Cr (VI). The method was successful applied to determination of Cr(VI) in wastewater samples from a leather dyeing industry. copyright The Electrochemical Society.

Estrategias individuales y colectivas de capital social: el impacto de programas públicos en dos comunidades campesinas: los casos de Ajial de Quiles y Cerro Blanco, VI Región de Chile

Incluye Bibliografía

Reunión de Trabajo sobre Encuestas Comparativas de Fecundidad en la América Latina, 1963: documentos, tomo VI

Incluye Bibliografía

Evaluacion y correccion de datos demograficos. VI. Analisis de la poblacion por edades

Capítulos de este documento disponibles separadamente (2945.00, 4912.00, y 3336.00)

ILPES: propuesta de agenda para la VI Conferencia de Ministros y Jefes de Planificación de América Latina y el Caribe (La Habana, 23-26 de marzo de 1987)

Presenta la propuesta de agenda para la Sexta Conferencia de Ministros y Jefes de Planificación de América Latina y el Caribe, e incluye versión preliminar para discusión interna del documento El desarrollo de América Latina y el Caribe: escollos, requisitos y opciones", preparado para el Período Extraordinario de Sesiones de enero de 1987 en México"