Scientists said Thursday they have isolated a target in the brain that anti-depressants and cocaine latch onto, a finding that could help in developing better treatments for depression.

The target is a protein structure found on some brain cells. Scientists cloned the protein and showed that its activity was blocked by several anti-depressants, as well as cocaine and amphetamines."This really is the starting point" for the effect of many anti-depressants on the brain, said study co-author Susan Amara.

The work is presented in Thursday's issue of the British journal Nature by Amara.

The protein is called a norepinephrine transporter, or a noradrenaline transporter. They are the same thing.

Certain brain cells use norepinephrine to communicate by releasing bursts of it that the receiving brain cell absorbs. The job of the transporter is to terminate that signal by pulling norepinephrine back into the signaling brain cell.