Paul Greengard, Ph.D.
SUMMARY: Dr. Paul Greengard stated that a major step forward in his teamís attempts to discern how dopamine achieves its affects was the discovery of the molecule dopamine and cAMP-regulated phospho-protein, MW=32kDa (DARPP-32). The researchers discovered that DARPP-32 is involved in mediating the actions of virtually all neurotransmitters in all parts of the brain. According to Dr. Greengard, virtually every known drug of abuse works through DARPP-32. Greengard offered as evidence that fact that, in his teamís research, mice from which the researchers removed DARPP-32 no longer responded to drugs of abuse. Substances they studied included opiates, cocaine, and amphetamines. The same response was observed when antipsychotic medications were tested.