Enteric neuron numbers and sizes in Auerbach's plexus in the small and large intestine of adult and aged rats

-The effects of acute diabetes on the density and size of the myenteric neurons of the proximal colon of adult rats were investigated. The injection of streptozotocin was followed by a period of observation of seven days, during which the diabetic animals showed weight loss, excessive food and water intake, large urinary debt and hyperglicemia. The whole-mounts from the proximal colon were stained with the techniques of Giemsa and of the NADH-diaphorase, and the employment of these techniques made it possible to verify a decrease on the neuronal density and on the cell body size of the myenteric neurons in the colon of the diabetic rats. These observations were discussed in terms of the pathophysiology of the diabetes and the experimental protocol.KEY WORDS: acute diabetes, myenteric neurons, proximal colon.Efeitos morfoquantitativos do diabetes agudo sobre os neurônios mioentéricos do colo proximal de ratos adultos Efeitos morfoquantitativos do diabetes agudo sobre os neurônios mioentéricos do colo proximal de ratos adultos Efeitos morfoquantitativos do diabetes agudo sobre os neurônios mioentéricos do colo proximal de ratos adultos Efeitos morfoquantitativos do diabetes agudo sobre os neurônios mioentéricos do colo proximal de ratos adultos Efeitos morfoquantitativos do diabetes agudo sobre os neurônios mioentéricos do colo proximal de ratos adultos RESUMO -Foram investigados os efeitos do diabetes agudo sobre a densidade e o tamanho dos neurônios mioentéricos do colo proximal de ratos adultos. À injeção de estreptozootocina seguiu-se um período de observação de sete dias, durante os quais os animais diabéticos apresentaram perda de peso, ingestão excessiva de alimento e água, grande débito urinário e hiperglicemia. Os preparados de membrana do colo proximal foram corados pelas técnicas de Giemsa e da NADH-diaforase. A aplicação dessas técnicas permitiu constatar uma redução da densidade neuronal e do tamanho do corpo celular dos neurônios mioentéricos no colo dos ratos diabéticos. Essas observações foram discutidas em termos da patofisiologia do diabetes e do protocolo experimental. The research on the changes induced by experimental diabetes on the several tissues and organs of laboratory animals is quite large. Among those systems under investigation are the gastrointestinal tract and its intrinsic enteric nervous system, the neuronal network responsible for the control of the activities of the bowel. It is reported, for instance, that the myenteric neurons of the stomach, duodenum and cecum are numerically reduced in diabetes 1-3 , and that specific neurochemical groups show response patterns to diabetes which depend on the intestinal segment and the duration of the diabetic state 4-7 . These neuronal changes, as well as those associated to the autonomic innervation of the gut 8-10 , stand among the responsible by the clinical gastrointestinal symptoms of diabetes [11][12][13] . PALAVRAS-CHAVERecently, we described an increase in the NADHdiaphorase positive myenteric neuronal population in the duo...

Section: Discussioncontrasting

confidence: 93%

“…The histogram of Figure 1 resembles those of other investigations 31,32 , although neurons having areas above 800 µm 2 had not been recorded.…”

Section: Discussionsupporting

confidence: 73%

Morphoquantitative effects of acute diabetes on the myenteric neurons of the proximal colon of adult rats

Furlan

Molinari

Neto

2002

“…In addition, in the proximal jejunum of age-matched rats, neurons were found with areas equivalent to those described in this work 10 . Nevertheless, in this investigation, cell body areas above 602.4 µm 2 were not observed, while those authors reported the presence of a small proportion (less than 1%) of neurons measuring up to 750 µm 2 .…”

Section: Discussionsupporting

confidence: 49%

Evaluation of the areas of neuronal cell bodies and nuclei in the myenteric plexus of the duodenum of adult rats

Miranda-Neto

Furlan

Sant’Ana

et al. 2000

-This study compared the areas of cell body and nucleus profiles of the myenteric neurons in the antimesenteric and intermediate regions of the duodenum of adult rats. Five male rats were used. The duodenum was removed and dissected to whole-mount preparations, which were stained by the Giemsa technique. The areas of cell body and nucleus profiles of 100 neurons, 50 from each region, of each animal, were assessed with image analyser. Based on the global mean±SD of the areas of cell body profiles, neurons were labelled as small, medium or large. It was observed that the neurons did not differ significantly in size or incidence between the antimesenteric and intermediate regions. However, the nuclei of the small and medium neurons were significantly smaller in the latter region. It is discussed that the smaller nuclear size could be related to the cell bodies being slightly smaller on this region and to a possible smaller biosynthetic activity which would influence nuclear size.KEY WORDS: myenteric neurons, neuronal area, duodenum, rats. Avaliação das áreas dos corpos celulares e dos núcleos neuronais no plexo mientérico do duodeno de ratos adultosRESUMO -Este estudo comparou as áreas dos perfis dos corpos celulares e dos núcleos neuronais dos neurônios mientéricos nas regiões antimesentérica e intermediária do duodeno de ratos adultos. Cinco ratos machos foram usados. O duodeno foi removido e dissecado a preparados de membrana, os quais foram corados pela técnica de Giemsa. As áreas dos perfis dos corpos celulares e dos núcleos neuronais de 100 neurônios, 50 de cada região, de cada animal, foram avaliadas com analisador de imagens. Com base na média global±SD das áreas dos perfis dos corpos celulares, os neurônios foram classificados como pequenos, médios ou grandes. Foi observado que os neurônios não diferiram significativamente de tamanho ou incidência entre as regiões antimesentérica e intermediária. Contudo, os núcleos dos neurônios pequenos e médios foram significativamente menores na última. Discute-se que o menor tamanho nuclear poderia estar relacionado ao fato dos corpos celulares serem ligeiramente menores nesta região e a uma atividade biossintética possivelmente menor, que influenciaria o tamanho nuclear. PALAVRAS-CHAVE: neurônios mientéricos, área neuronal, duodeno, ratos.For many years the enteric nervous system (ENS) has been the goal of studies aiming, first, at unravelling its intricate structure, neuronal cell types, connections and neurochemical coding and, second, at understanding how these aspects are affected by factors such as age and pathophysiological Trabalho resultante de pesquisa realizada durante o mestrado de MMDP Furlan pelo

“…Nevertheless, most of the studies on the effects of malnutrition on the enteric neurons assess the small intestine 5,8,10,13,16 , the number of works dealing with the large intestine being reduced 1,11,12,14,15,17 . Studies in the ascending colon of rats subjected to protein deficiency during gestation and lactation demonstrated increased neuronal density and incidence of large neurons 11 , while animals subjected to apoproteic diet during gestation and lactation had changes in the myenteric ganglia shape, reduction in the area of the neuronal profile and greater density of the neurons in the total colon 17 .…”

mentioning

confidence: 99%

“…In what concerns the effects of undernourished on the myenteric plexus, the hypoproteic diet leads to a greater concentration of neurons 5,10-12 and diminishment of their numbers [13][14][15] . Nevertheless, most of the studies on the effects of malnutrition on the enteric neurons assess the small intestine 5,8,10,13,16 , the number of works dealing with the large intestine being reduced 1,11,12,14,15,17 .…”

mentioning

confidence: 99%

Effect of protein and vitamin B deficiency on the morpho-quantitative aspects of the myenteric plexus of the descending colon of adult rats

Araújo

Sant’Ana

Molinari

et al. 2003

We carried out this work with the purpose of studying the effects of protein and vitamin B deficiency on the morphologic and quantitative aspects of the myenteric plexus of the descending colon of adult Rattus norvegicus. Twenty-eight rats were divided in two groups, one of them receiving chow with 22% protein level (control) and the other fed with chow having 8% protein level without vitamin B supplementation, during 120 days. Whole-mounts of the descending colon were prepared and stained with Giemsa, NADH-diaphorase and NADPH-diaphorase. The undernourished rats had a body weight 11.84% less than the control group. Relative to the controls, the experimental group had a colonic area 48% smaller, 51.9% less Giemsa-stained neurons, 28.3% less NADH-diaphorase positive neurons and 24.2% less NADPH-diaphorase positive neurons.