Auerbach's plexus of the rat cecum in relation to the germfree state

Abstract

The cecum of germfree rats, after the second week of life, enlargpi sixfold over t h a t of conventional tank-raised controls. Poor muscle tone as well as dictary factors have been incriniinatcd. We have studied the niyenteric plcxus of thcecum in conventional and germfree rats, in a n effort to find a neuronal explanatio-1 o f the plienomcnon a n d to test whether the neurovcgetative periphery is capable of adapting to the changing size.With routine and histochemical technics three salient features stood out: ( 1 ) The myenteric neurones i n the cecum of the germfree rat on a n average were three times larger Lhan those of the controls (42 ,u vs 16 p ) . Somc ncurones of the germfree cecuni attained giant size (over 130 p). ( 2 ) They showed a lower DPNH diaphorasc activity, unrelated to the increased cell siLe. ( 3 ) In the germfree r a t cecum the mcshcs of the primary fiber plexus of Auerbach h a d increased in size along thc antimesenteric border, while the network under the mesenteric attachment was smaller. The ratio betw-een the network of the two sides w a s 1:12 in the germfrcc. 1:5 in the controls.Wc have concluded that the neurones of Auerbach's plcxus i n the germfree cecum are indeed less active metabolically -a factor which m a y perpetuate the cycle of cecal distention in these animals. Thc iicurovceetative periuherv i n the cecum has shnwn itself capable to responding to the trophy .

The number and profile of reactive NADH-d and NADPH-d neurons of myenteric plexus of six-month-old rats are different in the cecum portions

“…Similar result was obtained for the NADH-d neurons ( Table 2). The large variation in the number of neurons distributed on the different cecal portions is related to the presence of a larger amount of nerve fibers from neurons responsible for the innervation of the muscle fibers and the venous plexus penetrating the organ by the mesenteric border and the high motor activity in the basal region of the cecum (Dupont et al 1965, Snipes 1981, Roger et al 1991. In our work we observed that the farther from the mesenteric portions and basal region, the smaller the number of neurons.…”

“…The NADPH-d reactive neurons, on the other hand, had more evident bundles, especially in the mesenteric portion and next to the cecal ampulla. The presence of thick bundles in these portions is justified by their characteristics; in the mesenteric region, the neurons could contribute to the innervation of the smooth muscle fibers of the intestinal wall and the vascular plexus which penetrates it (MirandaNeto et al 2001) and, in the portion next to the cecal ampulla, the higher number of bundles is a result of the higher thickness of the muscular tunica and a high motor activity attributed to this portion (Dupont et al 1965, Snipes 1981, Roger et al 1991, Seyfert 2003.…”

“…Dupont et al (1965) evaluated the measurement of the reactive NADPH-d myenteric neurons in the A1 and A cecum portions (antimesenteric and mesenteric portions of the basal portion, respectively) from 30 Fisher rats. The cellular size was established by the sum of the two largest perpendicular diameters of each neuron divided by two.…”

“…Research on the morphofunctional characteristics of the cecum, in several animals, has paid attention to the intrinsic innervation. The rat is, by excellence, the main experimental model for functional studies, so the morphology and density of the myenteric neurons of this segment have been widely investigated in this species (Dupont et al 1965, Gabella 1971, Barbosa 1973, Bruns et al 1977, Snipes 1981, Roger et al 1991, Young et al 1992, Fregonesi et al 1998, Seyfert 2003. However, few authors have been concerned with the distribution of these neurons in the different cecum portions (Dupont et al 1965, Seyfert 2003.…”

Repercussões morfológicas da lesão térmica corporal nos componentes do plexo mioentérico do jejuno de ratos adultos.

“…Em seus primórdios, as análises dos neurônios entéricos foram feitas a partir da impregnação pela prata e azul de metileno (IRWIN, 1931;MATSUO, 1934;DUPONT et al, 1965 A estas técnicas de evidenciação de elementos neuronais somam-se outras como a histoquímica, a imunohistoquímica e a imunofluorescência (GABELLA, 1969;BENNET, 1973;BOR-SENG-SHU et al, 1994;SANTER, 1994;YOUNG et al, 1993).…”