-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...

-This study had as its purpose to assess the effects of acute diabetes induced by streptozotocin (35 mg/kg body weight) on the number and size of the myenteric neurons of the duodenum of adult rats considering equally the antimesenteric and intermediate regions of the intestinal circumference. Experimental period extended for a week. Neuronal counts were carried out on the same number of fields of both regions of the duodenal circumference and measurements of neuronal and nuclear areas on equal numbers of cells. Number and size of the myenteric neurons stained with Giemsa were not significantly different between groups. On the other hand, the proportion of NADH-positive neurons increased from 18.54% on the controls to 39.33% on the diabetics. The authors discuss that this increased reactivity probably results from a greater NADH/NAD + ratio, described in many tissues of diabetic animals, which has consequences on the modulation of the enzymes that use these cofactors and whose activity is detected by the NADH-diaphorase technique.KEY WORDS: duodenum, myenteric neurons, acute diabetes, NADH-diaphorase.Número e tamanho dos neurônios mientéricos do duodeno de ratos adultos com diabetes agudo RESUMO -Este estudo teve como objetivo avaliar os efeitos do diabetes agudo induzido por estreptozootocina (35 mg/kg de peso corporal) sobre o número e tamanho dos neurônios mientéricos do duodeno de ratos adultos considerando de forma equivalente as regiões antimesentérica e intermediária da circunferência intestinal. O período experimental se estendeu por uma semana. As contagens neuronais foram feitas em igual número de campos nas duas regiões da circunferência duodenal e as mensurações das áreas neuronais e nucleares em igual número de células. O número e o tamanho dos neurônios corados por Giemsa não foram significativamente diferentes entre os grupos. Por outro lado, a proporção de neurônios NADH-positivos aumentou de 18,54% nos animais controles para 39,33% nos diabéticos. Os autores discutem que essa maior reatividade possivelmente resultou do aumento da proporção NADH/NAD + , descrita em diversos tecidos de animais diabéticos, que repercute na modulação das enzimas que utilizam esses cofatores e cuja atividade é detectada pela técnica da NADHdiaforase. PALAVRAS-CHAVE: duodeno, neurônios mientéricos, diabetes agudo, NADH-diaforaseThe knowledge about the mammalian enteric nervous system (ENS) can be considered, currently, as wide and in some instances, quite deep. Descriptions found on the literature assess several aspects of this subdivision of the autonomic nervous system 1-5 and reveal the richness of structure and organization of this neuronal population of magnitude similar to that of the spinal Trabalho

We carried out this investigation with the purpose of verifying whether insulin treatment prevents changes in the density of myoenteric neurons of the duodenum of Wistar rats with streptozotocin short-term diabetes. The animals from the diabetic group (D) lost more weight than the controls (group C), while the insulin treatment (group T) prevented weight loss in three animals and increased visceral fat in all of the animals of this group. Insulin treatment did not prevent the early loss of HuC/HuD myoenteric neurons. The density of nNOS-positive neurons did not change significantly in groups D and T. The density of NADHd-positive neurons in these groups was greater than in group C, indicating that short-term diabetes increases the activity of respiratory chain enzymes.

The effect of severe food restriction since birth on regulation of fasting glycemia in male Wistar rats was investigated. The control group (CG) had free supply of chow, while the restriction group (RG) received 50% of the amount ingested by the CG. The experiments were done in adult (60 days) overnight fasted rats in which glycemia, liver free glucose levels and hepatic glycogen concentration were measured. In part of the experiments in situ liver perfusion was done. The results showed that livers from the RG had higher glycogenolysis rates but lower gluconeogenesis rates from L-alanine (10 mM). Since RG showed maintained glycemia during fasting, it could be concluded that livers from RG produced glucose preferentially from glycogenolysis in detriment of gluconeogenesis. These findings demonstrated that in spite of severe caloric restriction, the metabolic adaptations of the liver did exist to assure the maintenance of blood glucose for brain supply during fasting

Ketogenesis, inferred by the production of acetoacetate plus ss-hydroxybutyrate, in isolated perfused livers from 24-h fasted diabetic rats submitted to short-term insulin-induced hypoglycemia (IIH) was investigated. For this purpose, alloxan-diabetic rats that received intraperitoneal regular insulin (IIH group) or saline (COG group) injection were compared. An additional group of diabetic rats which received oral glucose (gavage) (100 mg kg(-1)) 15 min after insulin administration (IIH + glucose group) was included. The studies were performed 30 min after insulin (1.0 U kg(-1)) or saline injection. The ketogenesis before octanoate infusion was diminished (p < 0.05) in livers from rats which received insulin (COG vs. IIH group) or insulin plus glucose (COG vs. IIH + glucose group). However, the liver ketogenic capacity during the infusion of octanoate (0.3 mM) was maintained (COG vs. IIH group and COG vs. IIH + glucose group). In addition, the blood concentration of ketone bodies was not influenced by the administration of insulin or insulin plus glucose. Taken together, the results showed that inspite the fact that insulin and glucose inhibits ketogenesis, livers from diabetic rats submitted to short-term IIH which received insulin or insulin plus glucose showed maintained capacity to produce acetoacetate and ss-hydroxybutyrate from octanoate.