In a corresponding study there at Karolinska
http://ki.se/ki/jsp/polopoly.jsp?l=e...20&newsdep=130
It was shown that dopamine is acting as a "switch" to turn on or off production of new neurons, brain cells.
I thought it was particularly interesting that in the salamanders that were being treated with l-dopa, this function of dopamine is inhibited- so that
no new stem cells are created!!
"When the salamanders were treated with L-dopa, the production of new dopamine-producing neurons was almost completely inhibited and the animals were unable to recover..."