Effects of the neonatal treatment with monosodium glutamate on myenteric neurons and the intestine wall in the ileum of rats

Abstract

The treatment with MSG did not cause alteration of the total myenteric population of the ileum, but it influenced the NADH-diaphorase-positive subpopulation. From the maintenance of the morphometric parameters of the ileum intestinal wall, we inferred that intestinal function was preserved in obese animals.

Avaliação do crescimento corporal e dos neurônios mioentéricos de ratos Wistar após tratamento neonatal com glutamato monossódico

“…It is established that rodents neonatally treated with MSG become obese adults with reduced nasoanal length, body weight and relative weight of organs (Pizzi and Barnhart, 1976;Bakke et al, 1978;Hamaoka and Kusunoki, 1986;Nakai et al, 1986;Remke et al, 1988;Yamamoto et al, 1993). The results of the present investigation concerning these parameters are in accordance with the literature.…”

“…The Lee index is regarded as an indirect indicator of obesity in MSG-treated rats (Bernardis and Patterson, 1968) and is often presented in studies of experimental obesity (Pizzi and Barnhart, 1976;Bakke et al, 1978;Scallet and Olney, 1986;Betran, 1992;Soares et al, 2006), although its accuracy and validity have been questioned by some authors (Cox et al, 1985;Stephens, 1980). On the other hand, the accumulation of adipose tissue in group MSG, given by the greater relative weight of the retroperitoneal and periepididymal fats, confirms that the treatment caused obesity.…”

“…The greater efficiency in the storage of nutrients as fat was ascribed both to the autonomic impairment and the disturbance of the hypothalamic actions of leptin due to the ARC lesion caused by MSG (Bray, 1984;Dawson et al, 1997;Martins et al, 2004). Other changes which disturb glucose homeostasis, such as hyperinsulinemia, insulin resistance and imbalances of glucocorticoid activity (Sartin et al, 1985;Yamamoto et al, 1993;Hirata et al, 1997;Macho et al, 2000), must also be involved.…”

“…Despite the effects of the ARC lesion by MSG on many metabolic, physiologic and behavioral aspects being well documented in the literature, only recently this experimental model was employed to investigate its effects on the myoenteric neurons (Soares et al, 2006). Therefore, this work aimed at evaluating how the neonatal treatment with MSG affects several body parameters, such as ponderal and linear growth, weight of organs and adipose tissue, and whether it causes alterations in the number and size of the myoenteric neurons of the stomach and duodenum of Wistar rats.…”

Características nociceptivas e histomorfométricas de nervos medianos de ratos com obesidade induzida pelo glutamato monossódico

“…Esses achados corroboram os de Roman-Ramos et al, 16 que citam que tal modelo de obesidade apresenta, além de aumento da resistência à insulina, alterações inflamatórias crônicas observadas em obesos com diabetes tipo 2. Miranda et al 23 citam ainda hiperatividade vagal nesse modelo de obesidade, que é característica da obesidade em humanos, ou seja, alteração no equilíbrio do sistema nervoso autônomo, que pode ser originada por lesão de células do núcleo arqueado hipotalâmico e áreas adjacentes, que o MSG produz.…”