Structures and Pathways of the Central Nervous System are Potentially Involved in the Serotonergic Modulation of GIT Activity
Abstract
The supposed involvement of rat brain regions in the modulation of rat small intestine serotonergic activity was investigated. Small electrolytic lesions were placed in the areas of medulla oblongata and pons Varoli; one week later; changes in the serotonergic response of the intestine were detected.
The contractions mediated by the activation of 5-HT2 receptors in the proximal ileum were, investigated. The whole ileum segments were cut and placed into the bath.
The preparations were contracted by adding increasing concentrations of 5-hydroxytryptamine (5-HT) (10 nM-1 muM) and noncumulative concentration-response curves (CRCs) were established. The differences between 5-HT responses of preparations from either sham-operated or experimental rats suggest the existence of brainstem regions (dorsal vagal and solitary nuclei, parvocellular reticular nuclei and serotonergicA(1.2.5) groups) that either stimulate or inhibit 5-HT modulatory action in the rat gastrointestinal tract.