Identification of serotonergic 5HT-3B type receptors in broiler’s small intestine
in broiler’s small intestine. Investigation were carried out on isolated smooth muscle of the circular and longitudinal layer of the broilers small intestine (strip dimension 3-4 mm x 2 cm). The muscle strips were placed in an isolated organ bath. The mechanical activity of the preparations were recorded via an isotonic force transducer coupled to a pen recorder. This was done following the addition of serotonin (nonselective 5-HT agonist), 2-Me-5HT (5-HT3B agonist) and Y-25130-hydrochloride (selective 5-HT3B antagonist). The research established a presence of serotonergic 5HT3B type receptors within the smooth musculature of the small intestines of broilers (COBB 500). The 5HT3B type receptors were present in smooth muscles of duodenum, jejunum and ileum, especially in longitudinal smooth muscles since this layer reacted even to low serotonin concentration (10-6). Statistical tests of obtained results showed significant differences (p< 0.001) in responses related to muscle layers, applied concentrations and intestinal parts which were observed. In the light of these findings, we suggest that investigated substances may have considerable physiological and therapeutic implications in disturbed function of small intestine of broiler’s.