Post-Weaning Protein Malnutrition Increases Blood Pressure and Induces Endothelial Dysfunctions in Rats

Malnutrition during critical periods in early life may increase the subsequent risk of hypertension and metabolic diseases in adulthood, but the underlying mechanisms are still unclear. We aimed to evaluate the effects of post-weaning protein malnutrition on blood pressure and vascular reactivity in aortic rings (conductance artery) and isolated-perfused tail arteries (resistance artery) from control (fed with Labina®) and post-weaning protein malnutrition rats (offspring that received a diet with low protein content for three months). Systolic and diastolic blood pressure and heart rate increased in the post-weaning protein malnutrition rats. In the aortic rings, reactivity to phenylephrine (10−10–3.10−4 M) was similar in both groups. Endothelium removal or L-NAME (10−4 M) incubation increased the response to phenylephrine, but the L-NAME effect was greater in the aortic rings from the post-weaning protein malnutrition rats. The protein expression of the endothelial nitric oxide isoform increased in the aortic rings from the post-weaning protein malnutrition rats. Incubation with apocynin (0.3 mM) reduced the response to phenylephrine in both groups, but this effect was higher in the post-weaning protein malnutrition rats, suggesting an increase of superoxide anion release. In the tail artery of the post-weaning protein malnutrition rats, the vascular reactivity to phenylephrine (0.001–300 µg) and the relaxation to acetylcholine (10−10–10−3 M) were increased. Post-weaning protein malnutrition increases blood pressure and induces vascular dysfunction. Although the vascular reactivity in the aortic rings did not change, an increase in superoxide anion and nitric oxide was observed in the post-weaning protein malnutrition rats. However, in the resistance arteries, the increased vascular reactivity may be a potential mechanism underlying the increased blood pressure observed in this model

Comportamento da cv. Pérola(Phaseolus vulgaris L.) Submetida a diferentes níveis de desfolha artificial Effect of Different levels of defoliation on productivity of common beans (Phaseolus vulgaris L. cv. Perola)

Estudos sobre desfolha artificial são muito úteis, principalmente para simular danos às plantas, como os causados por insetos ou granizo, por exemplo. Em trabalhos com o feijoeiro, ficou evidente que os resultados são altamente dependentes da cultivar utilizada e das condições climáticas prevalecentes. Objetivou-se com este trabalho avaliar a redução na produtividadedevida à redução artificial da área foliar da cv. Pérola nas condições de Rio Branco, AC. O experimento foi conduzido no campo experimental da Embrapa Acre, em delineamento de blocos casualizados, com quatro repetições e esquema experimental de parcelas subdivididas, estudando-se nas parcelas cinco das etapas de desenvolvimento da planta (V3= primeira folha trifoliolada, V4= terceira folha trifoliolada, R6= floração, R7= formação de vagens e R8= enchimento de vagens) e nas subparcelas, quatro níveis de desfolhamento (0%, 33%, 66% e 100%). Foram avaliadas, em média, 480 plantas nas 4 linhas centrais de cada subparcela, determinando-se o número de vagens por planta, o número de grãos por vagem e a produtividade de grãos. Paralelamente, em uma área adjacente, foram colhidas, ao acaso, 50 plantas de cada etapa de desenvolvimento para a obtenção da área foliar média. Nas etapas de desenvolvimento V3, V4 e R7, níveis de desfolhamento a partir de 33% causaram decréscimo no número de vagens por planta. O número de sementes por vagem não sofreu influência dos níveis de desfolhamento das plantas. O rendimento dos grãos foi significativamente reduzido à medida que as plantas foram submetidas a níveis crescentes de desfolha. A etapa de florescimento (R6) foi a que apresentou maior redução na produtividade como resposta à desfolha.<br>Studies to evaluate artificial defoliation are very useful, mainly to simulate damages to plants, such, as the ones caused by insects or hail. Experiments with bean plant, indicated that the results are higly dependent on the cultivars used, and preponderant climatic conditions. The purpose of this study was to evaluate yeld reduction due to the reduction on the leaf area at different stages of growth of bean crop of Perola cultivar under environmental conditions of Rio Branco, Acre. The experiment was conducted at the Experimental Station of Embrapa Acre. The experiment was arranged as a split-plot in a randomized block design, with four replications. The main plots consisted of five plant development stages: V3= first trifoliate leaf, V4= third trifoliate leaf, R6= initiation of flowering , R7= pod formation and R8= pod maturation, and the sub-plots were the four defoliation levels (0%, 33%, 66% and 100%). At harvest an average of 480 plants of the four central lines of each sub-plot were evaluated. It was determined the number of pods per plant, number of seeds per pod and yeld (kg/ha). In order to determine the average leaf area, 50 plants were randomily harvested in each development stage. The results demonstrated that defoliation levels starting from 33%, in the stages V3, V4 and R7, reduced the number of pods per plant. The number of seeds per pod was not affected by the level of defoliation of the plants. The seed weight was significantly reduced as the plants were submitted to increasing levels of defoliation. The flowering stage (R6) presented the highest yeld reduction with defoliation of the plants