A graph of scientific articles published per year which mention four major neurotransmitters in their title:
What I take from this is
- Dopamine is king! And with great popularity, comes great misrepresentation.
- What happened to glutamate research in the mid 1990s?
- The recent hype about oxytocin doesn’t seem to be driven by a spike in the primary literature.
- Nor does the hype about serotonin. Yes, publications increase on this neurotransmitter, but not compared to glutamate. And most people haven’t heard about glutamate, despite it being more abundant.
Technical note: I scraped the data from google scholar using scholar.py by Christian Kriebich
Update: here’s the raw data, should you want it
Mind Hacks 
LTP happened to glutamate research in the 1990s! You couldn’t go anywhere with papers on glutamate and NMDA and mGluR receptors and subsequent second signalling, quantal release and all of that good stuff. LTP is a great example of a cumulative research programme in neuroscience where lots of the really big problems got solved in consequential ways.