Neuron / neurotransmitter selection question

yan king yin y.k.y at lycos.com
Sat Mar 8 20:33:42 EST 2003


"John H." <johnh at faraway.xxx> wrote in message news:<ZPj7a.243$6r2.6767 at nnrp1.ozemail.com.au>...
> Last year I did read some research to the effect that administration of BDNF
> switched a cardiac neuron from excitatory to inhibitory function in under 15
> minutes. Sounds weird I know and have no idea about how it could work. If
> you like will try to find the reference in my archives. No, here it is
> 
> 04/07/02 6:50
> Nature Neuroscience
> Published online: 6 May 2002, doi:10.1038/nn853
> June 2002 Volume 5 Number 6 pp 539 - 545
> 
> A rapid switch in sympathetic neurotransmitter release properties mediated
> by the p75 receptor
> 
> Bo Yang1, 2, John D. Slonimsky1, 2 & Susan J. Birren1
> 
> 1. Department of Biology, Volen Center for Complex Systems, 415 South St.,
> M/S 008, Brandeis University, Waltham, Massachusetts 02454, USA
> 2. The first two authors contributed equally to this work.
> Correspondence should be addressed to S J Birren. (e-mail:
> (/neuro/email_response/email.taf?address=birren%40brandeis.edu))
> Cardiac function is modulated by norepinephrine release from innervating
> sympathetic neurons. These neurons also form excitatory connections onto
> cardiac myocytes in culture. Here we report that brain-derived neurotrophic
> factor (BDNF) altered the neurotransmitter release properties of these
> sympathetic neuron-myocyte connections in rodent cell culture, leading to a
> rapid shift from excitatory to inhibitory cholinergic transmission in
> response to neuronal stimulation. Fifteen minutes of BDNF perfusion was
> sufficient to cause this shift to inhibitory transmission, indicating that
> BDNF promotes preferential release of acetylcholine in response to neuronal
> stimulation. We found that p75-/- neurons did not release acetylcholine in
> response to BDNF and that neurons overexpressing p75 showed increased
> cholinergic transmission, indicating that the actions of BDNF are mediated
> through the p75 neurotrophin receptor. Our findings indicate that p75 is
> involved in modulating the release of distinct neurotransmitter pools,
> resulting in a functional switch between excitatory and inhibitory
> neurotransmission in individual neurons
> --
> 
> This is a good example, however, of the variability of neural transmission.
> MANY factors can affect neurotransmitter release, some people in computers
> tend to assume that a neuron's function is 'fixed'. I wish, that would make
> so much that much easier. To my knowledge the above is the only reference I
> have seen to this change in function. Your question may be somewhat
> academic, many neurons receive multiple inputs from a variety of other
> neurons, altering action potentials this way and that. For excellent egs of
> this have a look at Goldman-Rakic's work on prefrontal circuitry. If you
> wish can forward references for free downloads of the relevant articles but
> warned you'll be quickly confused. I'm happy to leave such problems to minds
> bigger than mine.

Thanks for giving this example, its always good to know the full range
of complexity of the nervous system... However this one may have an
explanation: During development, neuronal precursors differentiate
into various sub-types, and it is precisely the neurotrophic factors
that determine which precursors develope into what sub-types. This
could be a result of that, rather than what happens under physiological
conditions. Does that make sense?

YKY

PS. Do tell me the Goldman-Rakic articles.. Im very curious about them...

> John H.
> 
> "Neo" <neo55592 at hotmail.com> wrote in message
> news:4b45d3ad.0302242023.28eb8978 at posting.google.com...
> > My background is in computers and not in biology so my question may
> > seem off. I would like to know if a neuron can select which
> > neurotramitter to release in synapses. Can a neuron select different
> > neurotranmitter for each action potential? How/why does a neuron
> > select different neurontransmitters?



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