I'd favour treating peptides separately for several reasons 1) there are so many of them - think more than 100 now recognised as neuronal messengers
2) they seem to be universal, been suggested that every neurone also makes one or more peptide messenger
3) peptides seem to be always co expressed with a conventional neurotransmitter
4) peptides are in large dense cored vesicles not in small synaptic vesicles, and these are not conspicuously targeted to nerve endings, so are probably not particularly released synaptically
I think therefore that what is generally true of conventional neurotransmitters is not generally true of peptide messengers. There are some possible exceptions of peptides that do look like conventional transmitters (Substance P) but I think these are exceptions.
So I suggest this article is better focussed on the conventional transmitters and peptides treated separately?Gareth Leng 08:34, 11 February 2007 (CST)
I think the "types of neurotransmitters" section and the "Common neurotransmitters" sections should be merged. - Robert Badgett 09:20, 20 January 2008 (CST)
Merger from Neurotransmitters
The page Neurotransmitters (along with all the contents of the subpages) may be merged with this page and redirected from Neurotransmitters. Any volunteer please? Supten Sarbadhikari 22:55, 22 September 2008 (CDT)
- Hi Supten,
- I'll do it. In about 30 minutes.
- Thanks Pierre-Alain Supten Sarbadhikari 00:06, 23 September 2008 (CDT)
Neurotransmitters are chemicals that are used to relay, amplify and modulate electrical signals between a neuron and another cell.
This definition is WP's. It appears to be derived from the MeSH entry " neurotransmitter agents". Obviously, neurotransmitters are not "used" (by whom? God?).
Pierre-Alain Gouanvic 01:45, 23 September 2008 (CDT)
- Hey Daniel (Mietchen)!
- You were on the definition as well! So now we have:
A class of body-internal chemicals used to relay, amplify and modulate electrical signals between a neuron and another cell.
- would you agree with:
A class of brain chemicals which relay, amplify or modulate electrical signals between a neuron and another cell.
- Pierre-Alain Gouanvic 01:58, 23 September 2008 (CDT)
- Several comments. First change would be:
A class of chemicals that carry or modify information generated or received by neurons.
- Let me elaborate.
- First, while there may be an associated change in membrane potential that gates a channel, the fundamental message transmission is chemical rather than electrical; the chemical is more specific. Think of a reuptake inhibitor that has activity on dopamine, norepinephrine, and serotonin. "Electrical" really doesn't convey that it is affecting three separate transmitter-receiver systems (i.e., presynaptic postsynaptic)
- Second, is this truly between neurons alone? When bradykinin stimulate a nociceptor, is that neurotransmission? If not, what should it be called? What about acetylcholine sent from a neuron to a muscle cell?
- Third, these aren't the only chemical communications system in the body. Should we have an agreed-on term for all chemicals that are part of signaling, such as cellular immunity; neurotransmitters and neuromodulators and neurotransmitter receptor antagonistss are a separate subclass of this master class? What are second messengers generated from a first neural event? Howard C. Berkowitz 09:02, 23 September 2008 (CDT)