I may be putting words into Toussaint's mouth, but perhaps your comment
fails to address "at the SAME TIME" (emphasis added). Certainly, a
neuron may release more than one transmitter (contrary to what I was
taught in grad school) "on the same day" or even within the same hour
or minute, etc., but if you slice the time finely enough, can it
co-release AT THE SAME TIME? Lest this be an experimental
indeterminancy, let us specify: can it co-release within, say, a 10mSec
period? within a 0.5mSec period?
In this context, Toussaint might be asking whether the frequency of the
input signal (or any other parameter) necessary for release of one
transmitter can be the same for both--if so, are there other parameters
determining release of one but not the other? etc.
I know there are some REAL neuroscientists out there (not just "I play
one on TV/online"): any data? (I do know vaguely that type of release
may be relevant: mast cells, besides the degranulation they are
clasically known for can also release by a more graded method; true for
neurons also?)
F. Frank LeFever, Ph.D.
New York Neuropsychology Group
In <36ae1b05.402566239 at news.udel.edu> who at cares.com writes:
>>. 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
>>===============================================================
>>| Toussaint Gerthory | Phone : (+47) 73 59 44 6 |
>>| IDI/Gl>shaugen | Office: G232A |
>>| 7034 Trondheim, Norway | mail : toussain at idi.ntnu.no |
>>===============================================================
>>| " For God so loved the world that he gave his one and only |
>>| Son, that whoever believes in him shall not perish but |
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>>>>>