I think one might sagree that in the majority of situations, acute
administration of SSRIs will not increase synaptic 5HT levels
GS: Why? This does not sound right to me. I've never looked at the
literature for selective 5-HT reuptake inhibitors but I fail to see how
acute administration would not result in increases in [5-HT]e. After all,
monoaminergic reuptake blockers (such as cocaine) produce increases in
extracellular levels of DA and 5-HT in nucleus accumbens and ventral
pallidum (and probably lots of other places).
Glen
<dag.stenberg at nospam.helsinki.fi> wrote in message
news:a480u3$oco$1 at oravannahka.helsinki.fi...
>et_al at my-deja.com wrote:
> > On 7 Feb 2002 13:51:41 GMT, dag.stenberg at nospam.helsinki.fi wrote:
> >>et_al at my-deja.com wrote:
> >>> SSRIs don't actually increase serotonin levels.
> >>Yes, they do, provided that inhibitory autoreceptors are
downregulated...
> >>
> > Hmmm. These, among others, seem not to agree:
> > :: ................
>> I agree that the question of what happens in the serotonin synapses
> during SSRI treatment with or without autoreceptor blocking is not easy
> to answer, and different experimental approaches yield somewhat
> different results. (Some of the papers you cited addressed total (store +
> release) 5HT levels; I think the focus has to be put on release and
> extracellular concentrations).
> I think one might sagree that in the majority of situations, acute
> administration of SSRIs will not increase synaptic 5HT levels, and they
> will tend to decrease 5HT production. However, it is possible to devise
> situations where synaptic levels are increased. I have seen some of
> these results presented, and they make sense. There is disagreement
> over whether this is presently reliably feasible in patients, and how it
> relates to the antidepressive effect. I think my main point is that we
> are not ready to discard the serotonin hypothesis of mood improvement.
>> In all, I think that the question of how antidepressants affect
> serotonin release is interesting because of its importance and its
> complexity. Sadly, I do not have the resources to go for this research,
> so my reading is a bit sloppy also. I was aware of the various
> disagreements, though. (By the way, who is good at measuring tryphophan
> hydroxylase mRNA?)
>> Dag Stenberg
>