Gastrointestinal Motility Changes and Myenteric Plexus Alterations in Spontaneously Diabetic Biobreeding Rats

BACKGROUND/AIMS: Type 1 diabetes is often accompanied by gastrointestinal motility disturbances. Vagal neuropathy, hyperglycemia, and alterations in the myenteric plexus have been proposed as underlying mechanism. We therefore studied the relationship between vagal function, gastrointestinal motiliy and characteristics of the enteric nervous system in the biobreeding (BB) rat known as model for spontaneous type 1 diabetes. METHODS: Gastric emptying breath test, small intestinal electromyography, relative risk-interval variability, histology and immunohistochemistry on antral and jejunal segments were performed at 1, 8 and 16 weeks after diabetes onset and on age-matched controls. RESULTS: We observed no consistent changes in relative risk-interval variability and gastric emptying rate. There was however, a loss of phases 3 with longer duration of diabetes on small intestinal electromyography. We found a progressive decrease of nitrergic neurons in the myenteric plexus of antrum and jejunum, while numbers of cholinergic nerve were not altered. In addition, a transient inflammatory infiltrate in jejunal wall was found in spontaneous diabetic BB rats at 8 weeks of diabetes. CONCLUSIONS: In diabetic BB rats, altered small intestinal motor control associated with a loss of myenteric nitric oxide synthase expression occurs, which does not depend on hyperglycemia or vagal dysfunction, and which is preceded by transient intestinal inflammation.

Efectos de la tintura de Melissa officinalis l. sobre íleon aislado y en modelo de diarreas / Effects of Melissa officinalis L. tincture on isolated ileum and in diarrhea model

Se realizaron 2 estudios, uno in vitro en el íleon aislado de cobayo y otro in vivo en un modelo de diarreas en ratas, con el objetivo de corroborar la acción antiespasmódica de una tintura al 20 % de Melissa officinalis L. En el modelo in vitro se encontró que las dosis de 0,084, 0,169 y 0,338 mg/mL de solución nutricia provocan una disminución significativa (p < 0,05) de la contracción inducida con acetilcolina (10 mg/mL). En el estudio in vivo se determinó que las dosis de 16,9, 33,8 y 67, 6 mg/kg de peso disminuían el tiempo de aparición de la primera diarrea y su frecuencia. En ambos modelos el efecto estuvo en dependencia de las dosis. La tintura tuvo un efecto antiespasmódico en los 2 modelos utilizados y una acción antidiarreica sobre el modelo in vivo.

Two studies were carried out: one in vitro in the guinea pig isolated ileum, and the other in vivo, in a diarrhea model in rats, with the purpose of confirming the antispasmodic action of a 20 % Melissa officinalis L. tincture. In the in vitro model, it was found that the 0,084; 0,169 and 0,338 mg/mL doses of nutritious solution provoke a significant decrease (p < 0,05) of the acetylcholine induced contraction (10 mg/mL). In the in vivo study, it was determined that 16,9; 33,8 and 67,6 mg/kg of weight doses decreased the time of appearance of the first diarrhea, and its frequency. In both models the effect was dependent on the doses. The tincture had an antispasmodic effect in the two models used, and an antidiarrheic action on the in vivo model.