Posted by Shawn. T. on July 30, 2005, at 15:48:15
In reply to Indiplon, Lunesta-- what's the difference?, posted by Jakeman on July 30, 2005, at 1:06:05
Indiplon is selective for GABA-A receptors that contain the alpha1 subunit. The mechanism of action of Lunesta has not been well defined. Lunesta (eszopiclone) is the S-isomer of zopiclone. Zopiclone acts not only at GABA-A receptors that contain the alpha1 subunit, but also at GABA-A receptors that contain the beta2 and gamma2 subunits in the absence of the alpha1 subunit(http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=7901754). Lunesta seems to have a unique effect on sleep compared to the alpha1 selective drugs. This suggests that a mechanism of action involving GABA-A receptors that do not include the alpha1 subunit is probable. In mice that have had their alpha1 or beta2 subunit gene knocked out, the sedative effects of hypnotic drugs are reduced (http://jpet.aspetjournals.org/cgi/content/full/304/1/30). The implication is that a drug that affects GABA-A receptors with either the alpha1 subunit or the beta2/gamma2 subunit combination would be a more effective sedative than a drug that only affects alpha1 subunit containing receptors. I think that it's somewhat safe to conclude that eszopiclone has a similar mechanism of action to zopiclone.
Shawn
poster:Shawn. T.
thread:535502
URL: http://www.dr-bob.org/babble/20050728/msgs/535697.html