Posted by danf on November 7, 2000, at 7:21:56
In reply to Re: Article: Lithium increases brain volume ?, posted by danf on November 6, 2000, at 16:48:52
> Thanks, Scott...
Li, Na & KNa is predominatly an extra cellular ion, K intracellular.
Na high concentrations outside the cell, low inside. K high, concentrations inside the cell, low outside. part of the life force of cells are metabolic pumps that maintain these concentration differences. The different concentrations cause an electric potential to exist across the membrane. When a nerve cell is depolorized, Na & K ions go thru the cell walls to try to attain equal concentrations.
Li which is not a "normal" life related ion has no specific metabolic controls ( as do Na & K ). When Li is present, it interferes with both the steady state ratios of Na & K ( Na & K 'pumps' ) as well as passage of the Na & K ions thru the membrane. It does this at low concentrations.
This corrsponds with therapeutic levels of Li used to treat bipolar.
At high concentrations, Li kills the cells by inactivating the 'pumps'.
There are no Li receptors. It does not have a complex molecular shape that binds to receptors of other molecules, as do neuro transmitters.
poster:danf
thread:47998
URL: http://www.dr-bob.org/babble/20001102/msgs/48345.html