5-HT7 receptors mediate the inhibitory effect of 5-HT on peristalsis in the isolated guinea-pig ileum.
The study was undertaken to investigate the 5-HT receptor mediating the inhibitory effect of 5-HT on peristalsis in the guinea-pig isolated ileum. The facilitatory and inhibitory effects were measured as the decrease and increase, respectively, in the intraluminal pressure required to trigger peristalsis. In the presence of 5-HT(2/3&4) receptor antagonists ketanserin (0.1 micro M), granisetron (1 micro M) and SB-204070 (1 micro M), a cumulative addition (0.1-100 micro M) of 5-HT or 5-carboxamidotryptamine, but not 2-methyl-5-HT produced a concentration-dependent increase in the threshold required to trigger peristalsis. The 5-HT(7) receptor selective antagonist SB-269970-A (0.01-1 micro M) or methiothepin (0.01-0.1 micro M) concentration-dependently antagonised this response to 5-HT. SB-269970-A (1 micro M) and methiothepin (1 micro M) were also able to restore peristalsis in tissues in which peristalsis was inhibited by a prior addition of 30 micro M of 5-HT. The results indicate an involvement of 5-HT(7) receptors in the inhibitory effect of 5-HT on peristalsis in the guinea-pig ileum.
Tuladhar
Bishwa R
BR
Bradford School of Pharmacy, University of Bradford, Bradford BD7 1DP. B.R.Tuladhar@bradford.ac.uk
Ge
Lanbo
L
Naylor
Robert J
RJ
D000818:Animals; D004146:Dioxanes / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D017829:Granisetron / Q000494:pharmacology; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects*; D066298:In Vitro Techniques; D007650:Ketanserin / Q000494:pharmacology; D010528:Peristalsis / Q000187:drug effects* / Q000502:physiology*; D010636:Phenols / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000187:drug effects* / Q000502:physiology*; D012701:Serotonin / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000502:physiology*; D013449:Sulfonamides / Q000494:pharmacology
D004146:Dioxanes; D017829:Granisetron; D007650:Ketanserin; D010636:Phenols; D010880:Piperidines; D011985:Receptors, Serotonin; D012701:Serotonin; D013449:Sulfonamides; C404922:SB 269970; C104425:serotonin 7 receptor; C084858:SB 204070A; C045918:2-methyl-5-HT; C047087:5-carboxamidotryptamine