Reuptake inhibitors (and selectivity)

[gymstud]

What does it mean to be sellective
In terms of
reuptake inhibtors

Apolgies for how badly worded my post is

 

[AlphaMethylPhenyl]

Can you elaborate?

Selectivity pertaining to what you're probably talking about corresponds to a receptor and/or nuerotransmitter

 

[Ceres]

selective means the reuptake inhibitor only acts on the specific receptor it's targeting, rather than a broad spectrum of similar receptors and receptor subtypes.

 

[AlphaMethylPhenyl]

I was wondering if the answer was that simple (i.e. the definition of selective)

 

[gymstud]

So ssri only works on seratonin
And its that simple?

 

[Ceres]

There are several seretonin receptor subtypes. Selective seretonin reuptake inhibitors target specific subtypes, rather than the whole group. The receptors are distributed to varying degrees in brain and body tissue. This is why SSRI's have an effect on the body aswell as the mental state.

 

[endotropic]

So ssri only works on seratonin
And its that simple?

Essentially yes. An SSRI increases the levels of serotonin in the synapse without affecting the other catecholamines (norepinephrine/dopamine). You can compare it to an SNRI (Serotonin/Norepinephrine Reuptake Inhibitor) which will increase levels of serotonin and norepinephrine without affecting dopamine.

A non-selective reuptake inhibitor would be something that increased serotonin, norepinephrine and dopamine.

There are several seretonin receptor subtypes. Selective seretonin reuptake inhibitors target specific subtypes, rather than the whole group. The receptors are distributed to varying degrees in brain and body tissue. This is why SSRI's have an effect on the body aswell as the mental state.

This isn't entirely correct. All SSRI target and inhibit the serotonin transporter, which takes serotonin out of the synapse. As far as I know the serotonin transporter only has one subtype, so an SSRI can't really be selective here.

Traditional psychedelics (5ht2a agonists) are selective in the way you're talking about, they effect only the serotonin subtype 2a receptor, without targeting the others.

 

[Epsilon Alpha]

Selectivity generally refers to the concentration of a drug which will produce a certain level of inhibition/binding competition, generally 50%, for a "target" (in this case a reuptake pump).

So suppose a drug inhibits (50% inhibition) SERT at 4nM and NET at 20nM, that means that at a 4nM concentration SERT would be 50% inhibited and NET would be less than 12.5%. The math is a bit more complex than this but you get the picture hopefully.