IUBio

Neurotransmitter Release ?

who at cares.com who at cares.com
Tue Jan 26 15:00:02 EST 1999


. Does it possible for a neuron to release several
>different type a neurotransmitter a the same time ? I read that neurons
>have several transmitter. 

Yes, co-release isnot uncommon. In fatc most neurons appear to contain
(and possibly release more then 1 NT.

>Can someone tell me if this mechanism is based on
>the frequency of the input signal/the area of the brain which is excited or
>both ?

The distribution of NTs varies with brainregion looked at.
There are nuclei conctaining serotonin mostly, noepinephrin mostly
etc. Also, whole tracts from brainstem al the way into the cortex can
have mainly 1 NT.
Likewize cortices (archi, paleo and neocortex) can have various NT's.

The mechanism of corelease depends on the input of the cell, like any
output of a neuron dpends on the spatio-temporal summation of it's
arboretic input at the axon-hillock.

Now, the next quetsion would be: how does "differential co-release"
work? Or, how does the cell vary the ratio of NT output?
This may be answered at a biochemical level:
the NTs ahve to be sythesized and therefore their presence depends on:
-precursors, enzymes, feedbackregulation (end-product-inhibition),
resorbtion from the cleft,etc.

Now enhanced expression of an enzyme that catalyzes the production of
one enzyme (e.g. tyrosine hydroxylse-leading to DOPA))  could
selectively lead to increased vesicular presence of
dopamine/(nor0epinephrine in the synnapse.
This is only one of mnay examples.

justus

 



>    By the way, is it possible for a neuron to distinguish a pain signal ?
>(does they release a special neurotransmitter ?)
>
>Thank you very much for any answer which can help me.
>--
>Gerth
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