Halogenation of 4-hydroxy/amino-3-methoxyphenyl acetamide TRPV1 agonists showed enhanced antagonism to capsaicin
作者:Dong Wook Kang、Yong Soo Kim、Kwang Su Lim、Myeong Seop Kim、Larry V. Pearce、Vladimir A. Pavlyukovets、Andy K. Tao、Krystle A. Lang-Kuhs、Peter M. Blumberg、Jeewoo Lee
DOI:10.1016/j.bmc.2010.09.001
日期:2010.11.15
As an extension of our analysis of the effect of halogenation on thiourea TRPV1 agonists, we have now modified selected 4-hydroxy(or 4-amino)-3-methoxyphenyl acetamide TRPV1 agonists by 5- or 6-halogenation on the aromatic A-region and evaluated them for potency for TRPV1 binding and regulation and for their pattern of agonism/antagonism (efficacy). Halogenation shifted the functional activity at TRPV1 toward antagonism with a greater extent of antagonism as the size of the halogen increased (I > Br > Cl), as previously observed for the thiourea series. The extent of antagonism was greater for halogenation at the 5-position than at the 6-position, in contrast to SAR for the thiourea series. In this series, compounds 55 and 75 showed the most potent antagonism, with K-i (ant) = 2.77 and 2.19 nM, respectively, on rTRPV1 expressed in Chinese hamster ovary cells. The compounds were thus ca. 40-60-fold more potent than 6'-iodononivamide. (C) 2010 Elsevier Ltd. All rights reserved.