Yale University researchers have cloned a gene that may shed light on how anti-depressant drugs and cocaine work.

The gene encodes the human noradrenaline transporter protein, a key component of the neural network leading to depression.

The transporter protein binds to the neurotransmitter noradrenaline, leading to the neurotransmitter's accumulation in nerve cells, said Susan Amara, who directed the study that was published today in Nature.

When the transport protein is blocked by anti-depressant drugs, the noradrenaline instead accumulates outside the cells, said Amara.

Understanding how neurotransmitters and drugs interact with the transport protein can lead to the design of better anti- depressant drugs, said Amara. Since cocaine binds to the transporter, knowledge of the protein may also help explain cocaine's actions.

Amara cautioned that the road to targeted anti-depressant drug development will be a long one since the transporter protein is just one early step along the complex network leading to depression.

The gene may also serve as a probe to identify individuals with abnormal transporter proteins, said Amara. Such individuals may expose a correlation between transporter gene defects and specific depressive disorders.

Amara said the university is filing for patent protection to cover the transporter protein. She was not aware of any company interest at this early stage. Companies developing anti-depressant drugs include Neurogen of Branford, Conn., American Home Products Corp. of New York, Eli Lilly & Co. of Indianapolis and Pfizer Inc. of New York.

-- Carol Talkington Verser, Ph.D. Special to BioWorld

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