A novel class of allosteric modulators of AMPA/Kainate receptors
Bioorg Med Chem Lett. 2009 Feb 15;19(4):1254-7. doi: 10.1016/j.bmcl.2008.12.094. Epub 2008 Dec 30
Cannazza G, Jozwiak K, Parenti C, Braghiroli D, Carrozzo MM, Puia G, Losi G, Baraldi M, Lindner W, Wainer IW
The rapid hydrolysis in vivo of IDRA21 to 2-amino-5-chlorobenzensulfonamide has been demonstrated by microdialysis experiments. The IDRA21 metabolite possess in vitro a biological activity similar to that of IDRA21 itself. Taking 2-amino-5-chlorobenzensulfonamide as lead compound, a novel class of AMPAR positive allosteric modulators has been prepared.
Interaction of bupropion with muscle-type nicotinic acetylcholine receptors in different conformational states
Biochemistry. 2009 Jun 2;48(21):4506-18. doi: 10.1021/bi802206k
Arias HR, Gumilar F, Rosenberg A, Targowska-Duda KM, Feuerbach D, Jozwiak K, Moaddel R, Wainer IW, Bouzat C
To characterize the binding sites and the mechanisms of inhibition of bupropion on muscle-type nicotinic acetylcholine receptors (AChRs), structural and functional approaches were used. The results established that bupropion (a) inhibits epibatidine-induced Ca(2+) influx in embryonic muscle AChRs, (b) inhibits adult muscle AChR macroscopic currents in the resting/activatable state with approximately 100-fold higher potency compared to that in the open state, (c) increases the desensitization rate of adult muscle AChRs from the open state and impairs channel opening from the resting state, (d) inhibits binding of [(3)H]TCP and [(3)H]imipramine to the desensitized/carbamylcholine-bound Torpedo AChR with higher affinity compared to the resting/alpha-bungarotoxin-bound AChR, (e) binds to the Torpedo AChR in either state mainly by an entropy-driven process, and (f) interacts with a binding domain located between the serine (position 6') and valine (position 13') rings, by a network of van der Waals, hydrogen bond, and polar interactions. Collectively, our data indicate that bupropion first binds to the resting AChR, decreasing the probability of ion channel opening. The remnant fraction of open ion channels is subsequently decreased by accelerating the desensitization process. Bupropion interacts with a luminal binding domain shared with PCP that is located between the serine and valine rings, and this interaction is mediated mainly by an entropy-driven process.