Posted by Viridis on July 4, 2003, at 3:33:03
In reply to Topamax works on GABA????, posted by galkeepinon on July 4, 2003, at 1:12:14
Based on a quick search, the proposed mechanism of action of Topamax actually involves three things (I'm paraphrasing from the Topamax website):
1) It's supposed to "enhance" the activity of GABA -- I didn't look into how it does this in detail, and I'm not sure anyone knows for certain.
2) It prevents certain other neurotransmitters (chemicals that carry messages from one brain cell to another) from binding to glutamate receptors; binding at these receptors can make key brain cells overexcitable, in contrast to the action of GABA at its receptors.
3) It "blocks sodium channels, thus decreasing excessive nerve-cell firing".
Basically, this means that by regulating the way certain charged atoms (ions; sodium in this case) move into or out of the cell, the rate at which the neuron sends messages to other neurons is decreased. This gets complicated (and I'm not an expert), but neuronal activity is highly dependent on the electrical charge differential inside the cell vs. outside. This is governed by the concentrations of ions (some positively charged, such as sodium, some negative). Limiting the ability of ions to flow into or out of the cell can prevent action potentials, essentially electrical "spikes" that cause messages to be sent to other neurons.
The goal of these meds is to keep the activity of crucial neurons at a normal level -- you want them to send warning signals when it's appropriate, but not be sending out these signals continuously. It's a bit like a thermostat -- if your house gets too cold, it should sense this and turn on the heat just long enough to fix the situation. But if it gets stuck and your furnace keeps pumping out heat, things can get pretty uncomfortable.
poster:Viridis
thread:239145
URL: http://www.dr-bob.org/babble/20030701/msgs/239165.html