Posted by Cam W. on May 17, 2000, at 19:21:46
In reply to SSRIs: Same or Different?, posted by PeterJ on May 17, 2000, at 17:49:43
Peter - The reason why SSRIs are act differently in different people is that they attach to receptors other than serotonin. Everyone has a different body make up and will react differently to SSRI attachment. This is partially what causes the different effects (eg anti-anxiety effect with Paxil). What the SSRIs all have in common is that they bind (and block) to the serotonin reuptake site on the presynaptic neuron. Although they are called "Selective" Serotonin Reuptake Inhibitors (SSRI), they do not bind 'only' to serotonin reuptake receptors (with the possible exception of Celexa).Here is a partial breakdown of other main receptors that different SSRIs affect:
Prozac - norepinephrine reuptake receptors, serotonin type 2C receptors.
Zoloft - dopamine reuptake receptors, sigma receptors.
Paxil - muscarinic/cholinergic, norepinephrine reuptake receptors, nitric oxide receptors.
Fluvoxamine - sigma receptors.
Attaching to these, and possibly other receptors can cause differences. Also, some of the SSRIs are metabolized selectively by different liver enzymes and in different ways, which can also affect their action.
Hope this helps - Cam
poster:Cam W.
thread:33808
URL: http://www.dr-bob.org/babble/20000517/msgs/33828.html