January 14th, 2010

Reports Reuters:

Most antidepressants — including the commonly used Prozac and Zoloft — work by increasing the amount of serotonin, a message-carrying brain chemical made deep in the middle of the brain by cells known as raphe neurons.

Researchers at Columbia University Medical Center in New York said on Wednesday that genetically engineered mice that had too much of one type of serotonin receptor in this region of the brain were less likely to respond to antidepressants.

“These receptors dampen the activity of these (serotonin-producing) neurons. Too much of them dampen these neurons too much,” Rene Hen of Columbia, whose study appears in the journal Neuron, said in a telephone interview.

“It puts too much brake on the system.”

Hen said the finding may be useful in giving doctors an idea of whether a patient will respond to an antidepressant.

And it could also help drugmakers populate better clinical trials to help identify new drug compounds that work for people who are unlikely to benefit from conventional antidepressants.

“The goal is to figure out something that is useful for the non-responders,” he said.

Find out more.