Posted by SLS on July 28, 2004, at 6:36:29
In reply to differences between ssri's, posted by shadowmon on July 28, 2004, at 2:05:23
> Is there any difference between which receptors that specific ssri's attach themselves to? I was just wondering why some people have different reactions to ssri's when in theory they are supposed to do the same thing.
I have nothing definitive to offer you, but any attempt to answer your question would make for a nice little research project.SSRIs, by description, attach themselves to the serotonin (5-HT) transporter and block access to it from the neurotransmitter. This is not a neurotransmitter receptor. (It is, however, a pharmacological receptor). The transporer is a carrier protein embedded in the cell membrane that transports serotonin molecules from outside the neuron (synapse) to the inside (cytosol) in order for them to be recycled. Most of the SSRIs attach themselves to other molecules in the body besides this transporter. They are not truly "specific" to the 5-HT transporter. They are, however, to various degrees, "selective", and tend to bind to the 5-HT transporter much more readily (tighter; with higher affinity) than to other receptors. How important are the actions of each individual SSRI drug at theses other biological sites to the differences seen in the clinical effects of these drugs is difficult to estimate.
One of the variables that is often neglected in discourse here regarding pharmacology is location. It is not important to know only what drugs do, but also to know where they do it. Drugs tend to find different areas of the brain to accumulate and exert their effects. Block some serotonin reuptake in the raphe, you ameliorate OCD; do it in projections to the amygdala, you get rid of social phobia. (This analogy might not be right). To make things more interesting, the same drug might have opposite effects in two different people. Is this a distribution thing or a circuit thing or a receptor polymorphism thing? Go figure that one out. Don't worry. They will. Soon. Just not soon enough. :-(
- Scott
poster:SLS
thread:371497
URL: http://www.dr-bob.org/babble/20040724/msgs/371532.html