Subject: What is the chemical composition of neurotransmitters?

Well, my question has two parts, but I couldn't fit both in the subject box. 

First of all, I'm asking because I'm doing a research paper on the chemistry 
of how the brain functions and its chemical reactions. I've been looking 
online for answers, but none seem quite right...

What I'm asking is first what makes up neurotransmitters (specifically 
acetylcholine, serotonin, and norepinephrine) in terms of elements (and in 
case I'm not being clear [a likely scenario] I mean in terms of the Periodic 
Table)? The other question that I wanted to ask was what is the chemical 
reaction between these neurotransmitters?

Thank you so much for you time, and I look forward to your answers!

Re: What is the chemical composition of neurotransmitters?