Thanks to Tony Breu’s frequent mention of ATPase in that serendipitous thread about treating hypokalaemia, I have learned a whole lot of important things this week. Here are some of my new insights, connecting to what I knew before.
Pumps and ion channels
I always throught that the sodium-potassium pump and the calcium-magnesium pump were ‘mechanisms’ or ‘principles’. I didn’t know they were actual things that you could point to and say, “There’s the pump.”
What I understand now is that these pumps are actually transporter channels, and that transporter channels are very similar to ion channels. The key difference is that in ion channels, ions pass through because of factors which don’t consume energy, whereas with transporter channels, you need energy to to push stuff through, and ATPase is the enzyme which… ummm… OK, this bit I would have to look up. Obviously, something to do with facilitating ATP and energy production… um… takes ATP and produces energy and knocks off phosphate atom? I give up.
The role of mitochondria and DNA
OK, to continue from where I still remember: ATP is an enzyme, which means it is a protein. I knew that much from the -ase bit. And as I recall, ATPase is produced by the mitochondria, and if my memory serves me correctly from my study of basic genetics, the mitochondria are factories for all proteins, with the recipes for these proteins coming from the nucleus in the form of mitochondrial DNA. (Dudes, don’t take this as fact, I am just telling you what I remember, OK?)
Now, this is pretty much the same as for ion channels, which are also proteins. And if your mother’s DNA said, “Here is our family recipe for Voltage-Gated Potassium Channels, dear,” but it’s not nearly as nice a recipe as aunt Betty’s recipe, then your mitochondria are going to be cooking up wonky ion channels, and you’ll have some lovely diseases and disorders, thanks to Ma’s family recipe. Oh, and if your own factory staff for whatever reason also mess up the cooking instructions, it compounds the problem. (Don’t blame your parents for everything, because it may be your body that copied down that recipe incorrectly. )
To put that back into genetics language: there are genes which encode all your various ion channels (i.e. they provide the recipes for those proteins), and if you have an allele (gene variant) which encodes ion channels that don’t do their job quite so nicely, you have a channelopathy (ion channel disease).
Pumps, channelopathies and sensory overstimulation
Most of the rather sparse literature on sensory overload is about people who have voltage-gated calcium channelopathies, and lots of autistic people have alleles which encode for calcium channelopathies.
Now, I hopped from discussing pumps (which are transporter channels) to talking about ion channels, so let’s go back to pumps for a moment. If you got a rather nasty family recipe for cooking up ATPase, or if your mitochondria have been taken over by anarchists, or whatever intracellular excuse you have for installing out-of-spec ATPase as pumps, then you’re gonna have a problem with maintaining an optimal balance of intra- and extracellular electrolytes even if your ion channels happen to be fine.
So, my present conclusion is that even suboptimal pumps could lead to sensory overload.
I’ll study some more to see whether this conclusion makes sense in the bigger scheme of things.
On my watch list…