In 2004 biotech firm Amgen began trials of a Parkinson's drug called glial cell line-derived neurotrophic factor, or GDNF.

FORBES: Magazine Article

They found that three others, most notably the antipsychotic clozapine, also prevented infection in human glial cells without the side effects.

BBC: NEWS | Health | Antipsychotics treat brain virus

It is made in cells called glial cells, which are usually thought to function merely as insulation for more important nerve cells.

ECONOMIST: Neurobiology

In 2004 biotech firm Amgen (nasdaq: AMGN - news - people ) began trials of a Parkinson's drug called glial cell line-derived neurotrophic factor, or GDNF.

FORBES: On The Cover/Top Stories