Premium
Involvement of 5‐ HT 3 and 5‐ HT 4 receptors in colonic motor patterns in rats
Author(s) -
Yu Y.,
Chen J.H.,
Li H.,
Yang Z.,
Du X.,
Hong L.,
Liao H.,
Jiang L.,
Shi J.,
Zhao L.,
Tan S.,
Luo H.,
Huizinga J. D.
Publication year - 2015
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/nmo.12550
Subject(s) - agonist , receptor , 5 ht receptor , 5 ht4 receptor , motility , serotonin , endocrinology , medicine , antagonist , biology , chemistry , neuroscience , microbiology and biotechnology
Background Colonic migrating motor complexes in the rat constitute two distinct propulsive motor patterns, pan‐colonic rhythmic long distance contractions ( LDC s), and rhythmic propulsive motor complexes ( RPMC s) occurring primarily in the mid/distal colon. Interstitial cells of Cajal govern their rhythmicity, but their occurrence is dependent on neural programs. Our aim was to investigate the involvement of 5‐ HT 3 and 5‐ HT 4 receptors in the generation and pharmacological control of the motor patterns. Methods Effects of 5‐ HT ‐related drugs on colonic motor patterns were analyzed through spatio‐temporal maps created from video recordings of whole organ motility. Key Results 5‐ HT 3 antagonists abolished RPMC s and LDC s. 5‐ HT 4 agonists inhibited LDC s; they promoted RPMC s, which was blocked by the 5‐ HT 4 antagonist GR 125487. 5‐ HT and the 5‐ HT 3 agonist m ‐ CPBG strongly inhibited LDC s and RPMC s. Conclusions & Inferences The generation of LDC s involves ongoing 5‐ HT release acting on 5‐ HT 3 and 5‐ HT 4 receptors. The spontaneous generation of RPMC s involves ongoing 5‐ HT release acting on 5‐ HT 3 but not 5‐ HT 4 receptors. Prucalopride and mosapride promote RPMC s, an effect that is inhibited by the 5‐ HT 4 receptor antagonist GR 125487. A 5‐ HT 3 agonist does not promote RPMC s. Segmentation, including a pattern of sequential segmental activity not previously described, can occur without significant involvement of 5‐ HT 3 and 5‐ HT 4 receptors. 5‐ HT and a 5‐ HT 3 agonist are strongly inhibitory indicating that 5‐ HT receptors are present in inhibitory pathways which are normally not involved in the generation of spontaneous or distention‐induced motor patterns.