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Naunyn Schmiedebergs Arch Pharmacol. 2008 Jul;378(1):125-37. doi: 10.1007/s00210-008-0282-y. Epub 2008 Apr 16.

The in vitro pharmacological profile of TD-5108, a selective 5-HT(4) receptor agonist with high intrinsic activity.

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Theravance, Inc., 901 Gateway Boulevard, South San Francisco, CA, 94080, USA.


The in vitro pharmacological profile of TD-5108, a novel, selective 5-HT(4) receptor agonist, was compared to that of clinically efficacious gastroprokinetic 5-HT(4) receptor agonists. TD-5108 produced an elevation of cyclic adenosine monophosphate in human embryonic kidney 293 cells expressing the human recombinant 5-HT(4(c)) (h5-HT(4(c))) receptor (pEC(50) = 8.3) and 5-HT(4) receptor-mediated relaxation of the rat esophagus (pEC(50) = 7.9) and contraction of the guinea pig colon (pEC(50) = 7.9). In all in vitro assays, TD-5108 was a high intrinsic activity agonist, unlike tegaserod, mosapride, and cisapride which, in the majority of test systems, had lower intrinsic activity. TD-5108 had high affinity (pK (i) = 7.7) and selectivity (> or =25-fold) for h5-HT(4(c)) receptors over other biogenic amine receptors. TD-5108 was >500-fold selective over other 5-HT receptors (including h5-HT(2B) and h5-HT(3A)) and, at 3 microM, had no effect on human ether-à-go-go-related gene K+ channels. In conclusion, TD-5108 is a selective 5-HT(4) receptor agonist in vitro. The high intrinsic activity and preferential binding of TD-5108 to 5-HT4 over other 5-HT receptors may result in an improved clinical profile for the treatment of gastrointestinal disorders of reduced motility.

[Indexed for MEDLINE]

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