Premium
5‐HT 4 receptors are not involved in the control of small intestinal transit in the fasted conscious rat
Author(s) -
CLAYTON N. M.,
GALE J. D.
Publication year - 1996
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1111/j.1365-2982.1996.tb00236.x
Subject(s) - receptor , 5 ht receptor , transit (satellite) , control (management) , chemistry , neuroscience , medicine , serotonin , psychology , computer science , engineering , artificial intelligence , public transport , transport engineering
Abstract Cisapride and metoclopramide are used clinically in the treatment of gastro‐oesophageal reflux disease and also in a variety of motility disorders of the gastrointestinal tract. Their prokinetic effect is thought to be due to the augmentation of acetylcholine release from the myenteric plexus, an effect likely to be mediated through the stimulation of 5‐HT 4 receptors. The role of 5‐HT 4 receptors in the control of intestinal motility in man and animals is not clear, therefore we have investigated their role in the control of small intestinal transit in the rat. Radioactive microspheres were administered into the proximal duodenum of fasted conscious rats through an indwelling cannula. The extent of small intestinal transit was examined by determining the distribution of the microspheres within the intestine. Following i.p. injection small intestinal transit was inhibited (78%) by atropine (3 mg/kg), suggesting the presence of a basal cholinergic influence. Furthermore, in the presence of p‐amino clonidine intestinal transit was stimulated (126%) by bethanechol (3 mg/kg). The 5‐HT 4 receptor agonists cisapride (1.0 mg/kg) and zacopride (1.0 mg/kg) failed to increase small intestinal transit. The 5‐HT 4 receptor selective antagonist GR125487 (1 mg/kg) was also without effect. These data suggest that 5‐HT 4 receptors are not involved in the control of small intestinal transit in the fasted conscious rat.