Effect of acute and repeated restraint stress on glucose oxidation to CO2 in hippocampal and cerebral cortex slices

It has been suggested that glucocorticoids released during stress might impair neuronal function by decreasing glucose uptake by hippocampal neurons. Previous work has demonstrated that glucose uptake is reduced in hippocampal and cerebral cortex slices 24 h after exposure to acute stress, while no effect was observed after repeated stress. Here, we report the effect of acute and repeated restraint stress on glucose oxidation to CO2 in hippocampal and cerebral cortex slices and on plasma glucose and corticosterone levels. Male adult Wistar rats were exposed to restraint 1 h/day for 50 days in the chronic model. In the acute model there was a single exposure. Immediately or 24 h after stress, the animals were sacrificed and the hippocampus and cerebral cortex were dissected, sliced, and incubated with Krebs buffer, pH 7.4, containing 5 mM glucose and 0.2 µCi D-[U-14C] glucose. CO2 production from glucose was estimated. Trunk blood was also collected, and both corticosterone and glucose were measured. The results showed that corticosterone levels after exposure to acute restraint were increased, but the increase was smaller when the animals were submitted to repeated stress. Blood glucose levels increased after both acute and repeated stress. However, glucose utilization, measured as CO2 production in hippocampal and cerebral cortex slices, was the same in stressed and control groups under conditions of both acute and chronic stress. We conclude that, although stress may induce a decrease in glucose uptake, this effect is not sufficient to affect the energy metabolism of these cells.

Participation of the cholinergic system in the ethanol-induced suppression of paradoxical sleep in rats

Sleep disturbance is among the many consequences of ethanol abuse in both humans and rodents. Ethanol consumption can reduce REM or paradoxical sleep (PS) in humans and rats, respectively. The first aim of this study was to develop an animal model of ethanol-induced PS suppression. This model administered intragastrically (by gavage) to male Wistar rats (3 months old, 200-250 g) 0.5 to 3.5 g/kg ethanol. The 3.5 g/kg dose of ethanol suppressed the PS stage compared with the vehicle group (distilled water) during the first 2-h interval (0-2 h; 1.3 vs 10.2; P < 0.001). The second aim of this study was to investigate the mechanisms by which ethanol suppresses PS. We examined the effects of cholinergic drug pretreatment. The cholinergic system was chosen because of the involvement of cholinergic neurotransmitters in regulating the sleep-wake cycle. A second set of animals was pretreated with 2.5, 5.0, and 10 mg/kg pilocarpine (cholinergic agonist) or atropine (cholinergic antagonist). These drugs were administered 1 h prior to ethanol (3.5 g/kg) or vehicle. Treatment with atropine prior to vehicle or ethanol produced a statistically significant decrease in PS, whereas pilocarpine had no effect on minutes of PS. Although the mechanism by which ethanol induces PS suppression is not fully understood, these data suggest that the cholinergic system is not the only system involved in this interaction.

Conceitos e estrutura mental

O objetivo da palestra foi o de apresentar um apanhado sucinto da história das investigações sobre conceitos nas últimas décadas, com isso contribuindo para a divulgação da Ciência Cognitiva. O episódio central dessa história é a guinada resultante das pesquisas realizadas por Eleonor Rosch e outros a partir do inicio dos anos setenta. Estas pesquisas colocam em cheque a CONCEPÇÃO CLÁSSICA DE CONCEITOS (caracterizada na primeira parte da exposição). O fato de que o abandono da concepção clássica não é uma alternativa viável, dá origem ao que chamamos de PROBLEMA DA CONCILIAÇÃO, ou seja, o de compatibilizar a concepção clássica com as descobertas modernas. A apresentação se encerra com algumas sugestões para a solução do problema.

Stanley Milgram, mies sähköshokkikoneen takana

Kirjallisuusarvostelu

Seminarios Talleres y Foros

Archivo Fotográfico

2004-05 Board of Trustees

The 2004-2005 Board of Trustees. Pictured here from left to right are: Front Row - Val Fleming; Dr. Patricia Teal; Wendy Staff; Dr. Norris Walker, Chair; Dr. David Atkinson, President and Vice Chancellor; Dr. Val Jaeger; Donna Scott; and Steven Lalinovich. Middle Row - Mike Farrell, Secretary to the University; Rudi Kroeker; Brandon Larry, President, Brock University Students' Union; Dr. Terry Boak, Vice-President, Academic and Provost; Mitzi Banders; Geeta Powell; Dr. Sid Segalowitz; Tom Gauld; Karin Jahnke-Haslam; and Dr. Mohammed Dore. Back Row - David Edwards, Immediate Past Chair; Bruce Wormald; Willy Heldbuechel, Vice-Chair; Brad Clarke; David Howes, Vice-Chair; Mark Steinman; Peter Partridge; Michael Sidenberg; Angelo Nitsopoulos; Steven Pillar, Vice President, Finance and Administration; Ron Dubien, Chief Information Officer. Absent from photo - Dr. Raymond Moriyama, Chancellor; Eleanor Ross; Jagoda Pike; Dr. Mary Frances Richardson; and Nick Brown.

Governor General Departs

The Governor General and his motorcade depart after the conclusion of the Official Opening of Brock University at the Glenridge Campus on October 19, 1964. Pictured here from left to right: F. G. Perry (with camera), African Students Foundation. Commander H. C. Tilbury (Hon, ADC). F/L Claude Filiatrault, (ADC-in-waiting). General Vanier. Madame Vanier. D. G. Wilmot. Dr. J. A. Gibson. Professor John Hart, University Marshal.

Physical Education Complex

Exterior view of the Phys. Ed. Complex after the 1980 Aquatic Centre Addition. The Eleanor Misener Aquatic Centre, which contains Brock's Olympic size swimming pool, is the large structure in the foreground. The remaining buildings in the background house the gymnasiums and other facilities.

Aquatic Centre Pillars

Work on the giant concrete pillars found in the Eleanor Misener Aquatic Centre.

Aquatic Centre Construction

Pouring the concrete in the construction of the Eleanor Misener Aquatic Centre.

Pool

Olympic size swimming pool in the Eleanor Misener Aquatic Centre.

Brock Pool

View of the pool inside the Eleanor Misener Aquatic Centre.

Agrarian revolution in Central America : a comparison of Nicaragua and Honduras using Jeffery Paige's theory of Agrarian revolution

ABSTRACT In 1979 Nicaragua, under the Sandinistas, experienced a genuine, socialist, full scale, agrarian revolution. This thesis examines whether Jeffery Paige's theory of agrarian revolutions would have been successful in predicting this revolution and ln predicting non-revolution in the neighboring country of Honduras. The thesis begins by setting Paige's theory in the tradition of radical theories of revolution. It then derives four propositions from Paige's theory which suggest the patterns of export crops, land tenure changes and class configurations which are necessary for an agrarian and socialist revolution. These propositions are tested against evidence from the twentieth century histories of economic, social and political change in Nicaragua and Honduras. The thesis concludes that Paige's theory does help to explain the occurrence of agrarian revolution in Nicaragua and non-revolution in Honduras. A fifth proposition derived from Paige's theory proved less useful in explaining the specific areas within Nicaragua that were most receptive to Sandinista revolutionary activity.

Report of the Committee to Whom was Referred the Memorial of Commodore Rodgers.

Caption title.