[Neuroscience] Re: Can a single neuron release multiple
(by m.kirkcaldie At removethis.unsw.edu.au)
Wed Jan 17 00:46:38 EST 2007
In article <Xns98ACD75D841C5polyfractalgmailcom At 220.127.116.11>,
Zachary Tong <polyfractal At gmail.com> wrote:
> I was curious if single neurons have the ability to release multiple
> neurotransmitters, or if each neuron was limited to one specific
> transmitter. If they can have multiple transmitters, how is it decided
> which transmitter is released? Are they all dumped into the synapse at the
> same time? My understanding is that vesicles are sensitive to calcium ion
> levels and will release their transmitters when the concentration reaches a
> certain point. This seems that if there are multiple types of
> transmitters, the vesicles would release them all at the same time.
> -Zachary Tong
During development it's been shown that neurons which release glycine in
the adult, "work up to it" by releasing GABA and glutamate at earlier
stages, and in fact developing neurons in the auditory brainstem nuclei
will release glutamate, GABA and glycine all at the same synapse, in
separate vesicles (Gillespie et al., Nature, 2005).
I doubt there would be a way to select between the transmitters for
release - after all an action potential is an action potential. However
I could imagine that secondary transmitters leaking back across the
synaptic cleft could influence the releasability of presynaptic vesicles
of different kinds. That's just a guess though.
I believe it's pretty normal for synapses to release transmitters and
co-transmitters at the same time - nitric oxide being the classic
example. The kinetics of each transmitter differ and so releasing
several kinds would allow different temporal firing patterns to have
different effects on the synapse. Seems potentially useful to me.
Hope that helps.
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