Posted by linkadge on April 24, 2007, at 16:14:40
In reply to Re: SSRI's and possible heart damage?! » linkadge, posted by nellie7 on April 24, 2007, at 14:34:21
The first thing that concerned me is that the SSRI's are going to be potent agonists of all 5-ht receptors including 5-ht2b. We already know that serotonin reuptake inhibitors can activate peripherial 5-ht receptors since GI upset is supposedly due to effects on GI serotonin transporters.
Another piece of information is that mice lacking the serotonin transporter, show similar cardiac damamge as that induced by the currently implicated medications.
http://circ.ahajournals.org/cgi/content/full/113/1/81
It is true that SSRI's do not completely wipe out the ability of the serotonin tranporter to clear serotonin, they can, in clincial doses reduce the activity of the serotonin transporter by some 60-80%.
My speculation is that the net activation of 5-ht2b is less than with direct 5-ht2b agonists, but the potential is still there to induce such problems given a larger time frame.
I am hoping more recearch is initiated promptly on the issue.
Certain SSRI's (like fluoxetine) have mild antagonistic effects on 5-ht2b which may (or may not) overcome the net increase in 5-ht2b transmission created by uptake inhibition, but I don't know if this would extend to other SSRI's.
Linkadge
poster:linkadge
thread:752704
URL: http://www.dr-bob.org/babble/20070419/msgs/753068.html