Some science behind the scenes

SSRIs

SSRI stands for Selective Serotonin Reuptake Inhibitor.  Selective serotonin reuptake inhibitors or serotonin-specific reuptake inhibitor (SSRIs) are a class of compounds typically used as antidepressants in the treatment of depression, anxiety disorders, and some personality disorders.

In normal circumstances, our cells take back unused and unwanted neurotransmitters and process them.  They package them up and carefully store them so that they can either be unpackaged and released again, or  expelled from the body [in our wee, for example] or turned into some other needed chemical. 

The cells act like small reprocessing factories turning what is not needed into what is needed.  Recycling unwanted chemicals.  They ‘take up’ the natural neurotransmitters - messengers  - that are swishing about our system for recycling and this is known as ‘Reuptake’. 

Reuptake inhibitors simply stop this process happening.  So whatever is happening at the time will happen longer.  If we are flooded with dopamine, we will just tend to carry on being flooded by dopamine – drunk with euphoria!  If we are full of adrenaline pumping away in giddy hyper energy  - fight and flight going strong – it happens longer, we carry on and on and on and on and on …… fighting and flighting!  They do this in a number of ways:

Standard Reuptake inhibitors – simply act as competitors to whatever neurotransmitter is meant to be taken up by the cell.  Thus in effect they occupy the ‘transporter’ – the input output route the neurotransmitter would have taken to be reused.  So in effect it is like putting a big blocking stone into the tunnel into the cell

Allosteric Reuptake inhibitors – attach themselves to the mechanism that controls the input and output of the neurotransmitter. So in effect, if we imagine a gatekeeper opening the gate into the tunnel a little or a lot depending on how much of the extra chemical needed to be taken back, these inhibitors nobble the gatekeeper so the gate is closed.

Two of the primary active constituents of the medicinal herb Hypericum perforatum (St. John's Wort), for example, are hyperforin and adhyperforin. Hyperforin and adhyperforin are inhibitors of the reuptake of serotonin, norepinephrine, dopamine, GABA, and glutamate  and they exert these effects allosterically.

Repackaging Reuptake Inhibitors – in order for the neurotransmitters to be reprocessed, they get packaged up and then stored in the cell in the thick liquid inside the cell [the cytoplasm]  Some inhibitors nobble the packer so the neurotransmitter is neither packed up or stored.  Instead of swishing about outside the cell looking for a receptor, it swishes about inside the cell looking for a packer that hadn’t been nobbled!  Here the neurotransmitter isn’t sent out again – so the concentrations of something like dopamine or serotonin for example swishing about in our systems [extra cellular] isn’t increased.  Instead, it just sits there waiting in the cell. So in a sense the concentrations are increased but only in the cell itself. They are there ready and waiting should something come along to release them. The disadvantage with these inhibitors is that long term, something that sits and waits unpackaged tends to degrade, so they may not increase the neurotransmitter capabilities by much.

Reuptake inhibitors are man made or come from plants. The body quite obviously is not going to prevent its own processes so all these drugs are externally administered.  There are illegal drugs and legal drugs and by far the most prevalent are the legal ones from pharmaceutical companies – although they actually do the same thing as the illegal ones.

References

A good collection of articles about SSRIs is to be found on http://www.erowid.org/chemicals/ssris/ssris.shtml

Observations

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