Brain chemical blamed for cell death.

By chemically synthesizing and studying the brain chemical dopegal in a tissue culture model of brain neurons, researchers at Saint Louis University School of Medicine have shown how the substance becomes toxic and accumulates in the cell, delivering a suicide message to brain cells in degenerative conditions such as Alzheimer's dementia. Neurons are the cells that carry out the functions of the brain, consisting of a cell body that contains genetic instructions together with the cell's biosynthetic machinery and a long projection called an axon, which reaches to the next neuron in the circuit. Neurons communicate with each other by chemicals called neurotransmitters that are transported from the cell body to the axon terminals where they are released. Neurotransmitters are the chemical messengers ultimately responsible for controlling memory, mood, movement, and behavior. When a neurotransmitter sends a message, a chemical stop order also must be conveyed to break the neurotransmission.

With a particular neurotransmitter, norepinephrine, dopegal is the first...