Posted by Viridis on July 4, 2003, at 2:57:35
In reply to Topamax works on GABA????, posted by galkeepinon on July 4, 2003, at 1:12:14
GABA is short for gamma-aminobutyric acid, which serves various functions, including regulating activity of some brain cells (neurons). In anxiety disorders (and some forms of epilepsy) neurons in certain regions of the brain are overactive, sending out messages to other neurons that in turn trigger anxiety, panic, or seizure. In many cases this seems to be because either there isn't enough GABA available in the spaces between the neurons (synapses), or the neurons don't respond to it appropriately. GABA kind of "puts the brakes on" when key neurons start speeding up their activity too much.
Receptors in the membranes (outer lining) of the neurons bind GABA, and this sends a message to the cellular machinery to limit the signals it sends to other neurons. If there aren't enough receptors, or they're somehow defective, the "damping" effects of GABA don't occur.
Various meds act by increasing the availability of GABA, enhancing its ability to bind to receptors, or mimicking its effects at the receptors. Benzodiazepines like Valium, Xanax, etc. bind to a different part of the GABA receptors than GABA itself and change their structure a bit, making it easier for GABA to bind. Neurontin is thought to be similar enough to GABA to fool the receptors, and so on. I'm not sure how Topomax works, but there are lots of ways to activate the GABA receptors and therefore decrease overactivity of the neurons.
poster:Viridis
thread:239145
URL: http://www.dr-bob.org/babble/20030701/msgs/239163.html