serotonin reuptake

[pauljohn]

  if serotonin reuptake is a natural process, necessary for normal, healthy neural functioning, why would doctors want to inhibit this with the use of ssri's in cases of patients with a depressive disorder?
 
 

[Steffen]

Reuptake means that there has to be something to be reuptaken in the first place. Even if serotonin has to be removed from the synaptic cleft, it still serves a function. This function might be disturbed if you have too little serotonin released from the presynapse. To compensate for the lack of neurotransmitter the reuptake is inhibited to keep it in the synaptic cleft and increase the probability of an effect on the postsynapse. That is: either you have an effect by a high amount of neurotransmitter, or you have it by keeping the transmitter in place for a little while. And in the end, of course, it has to be removed in both cases.
What exactly happens during depression I don't know, but I guess this is a general principle which might help answering your question.

[pauljohn]

thanks very much steffen. do you, or anybody else, know if the chemistry has been observed, ie, the reaction between the inhibitor and the serotonin itself?

(i'm assuming the inhibitor acts on the serotonin, but maybe it doesn't? maybe it acts on the reuptake pump? or maybe neither of these happen? maybe there is another reason for the inhibition?)

[Anand]

SSRIs do indeed act on the reuptake pump inhibiting its action and thus as a consequence increasing the amount of serotonin in the synapse.