Posted by Bruce on November 9, 1999, at 7:31:46
Got this off the Web:
New Target Of Depression Drugs FoundWASHINGTON (Reuters) - Researchers said Monday they had identified a new brain chemical that is affected by popular antidepressant drugs, and said it could be important in formulating new treatments for depression and severe premenstrual syndrome (PMS).
The chemical is known as a neurosteroid and is completely different from the neurotransmitters, or message-carrying chemicals, that are linked with mood, motion and other brain functions.
Writing in the Proceedings of the National Academy of Sciences, the team at the University of California San Francisco said top-selling antidepressants such as Prozac, Paxil and Zoloft all affect the chemical, known as allopregnanolone.
These antidepressants are all members of a class of drugs known as selective serotonin reuptake inhibitors (SSRIs), and are believed to help depression by increasing the availability of serotonin, a neurotransmitter associated with mood.
Synthia Mellon and colleagues at UCSF found they also work on a pathway that has only recently been found by scientists.
``Each of these three serotonin reuptake inhibitors, or SSRIs, shows a dramatic positive effect on the levels of allopregnanolone, a steroid made in the brain, which most likely modulates mood and plays a role in heightened anxiety and depression found in severe premenstrual disorders and other conditions,'' Mellon said in a statement.
All three drugs increase the synthesis of allopregnanolone by 10 to 30-fold, Mellon said.
``The study points to the likelihood that SSRIs control mood by more than the one pathway that has received most of our attention, and it suggests that the steroids synthesized in the human brain may play a strong physiological role in regulating anxiety and depression,'' she said.
Allopregnanolone is a byproduct of progesterone, one of the so-called female hormones. This could help explain why antidepressants such as Prozac -- which Food and Drug Administration advisers recently said should be approved for treating a certain severe form of PMS -- seems to help with the problem.
Mellon's team tested human and rat tissue and found the SSRIs affected allopregnanolone, while another kind of antidepressant, one from a class known as tricyclics, did not have any effect.
The idea is to make new and better drugs, Mellon said.
``We're interested in finding compounds that may directly affect these enzymes in the brain, and thus regulate mood disorders with minimal side effects,'' she said in a statement.
poster:Bruce
thread:14871
URL: http://www.dr-bob.org/babble/19991108/msgs/14871.html