3 ms·
Yeah, physician (pathologist, specifcally) with a degree in physics here. I'm going through articles in other tabs right now just because I'm skeptical enough t
by killjoywashere 3y ago
Yeah, physician (pathologist, specifcally) with a degree in physics here. I'm going through articles in other tabs right now just because I'm skeptical enough to consider crazy ideas (always good to build bulwarks), this is, at best hypothetical, but mainly the chain of causality in the above statements is a hot mess.
I spend a lot of time looking at cell membranes. More than almost all of humanity. The naive Fluid Mosaic Model is certainly incomplete, but let's let Dr. Nicholson himself (the author of the original description) have a chance to provide his update first (1). So, yes, there's lot of other stuff going on, but certainly the basic organizing concepts are intact.
I'll allow the idea that the transfer of ions across the membrane is a thermodynamic effect. Of course it is. The whole nitrogen vs helium thing works well enough in my mind with just "thermodynamics". Yeah, sure.
But this statement "The action potential itself is the propagation of this solid phase" does not pass the sniff test for me. The action potential is a self-propagating electric field tripping channels along the way, propagating along inner and outer surfaces of the membrane, the channels are what make it self-propagating. Nothing about the concept of "solid" makes sense at these scales in a biological system. Everything is just more or less bound, and that neighbor-to-neighbor binding is entirely secondary to the mammoth electrical field whipping down the axon.
(1) Nicholson GL, de Mattos GF. A Brief Introduction to Some Aspects of the Fluid–Mosaic Model of Cell Membrane Structure and Its Importance in Membrane Lipid Replacement. 2021. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8708848/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8708848/
- superkuh 3y agoYes, this is a contested theory, but it's not a crackpot theory. I'm well aware of the fluid mosaic model. It is not mutually exclusive with what I've described, in fact it's the base from which this theory is formed. And it is not my theory, but the theory first formulated by literally the guy that discovered the mechanism of action of myelinated action potentials (Ichiji Tasaki, who worked on it during his entire time at the NIH). Call it crackpot if you want but please don't do so just because you've misinterpreted a a short forum post trying to introduce a complex concept in a concise way. To clear it up for you, the transfer of ions across the membrane by ion channels is not something I'm debating. Nor am I saying that the electrical field isn't required for the action potential to propagate. If you took that away from my post I can understand you thinking it's crackpottery. I'm just saying it's not the whole picture. When there's lots of light gas anesthetic dissolved in the lipid membrane keeping the heat capacity low (disordered) it is thermodynamically harder (requires more energy) to form the organized 'solid' (actually more like a gel to be pedantic) state that propagates with/as the action potential. All these things are happening together, and more (like, how the lateral pressure profile might link the lipid state to ion channel conformational changes, etc). Simple electrical models cannot explain reversible uptake and release of heat (resistance cannot do this) with the passing of the action potential. Nor the reason atmospheric pressure changes dosage, nor the reason there's a change in optical birefringence and scattering. So you know what it describes is not the full picture. But don't take my word for it, go read Tasaki or Heimburg's work on this if you want to understand the detail. http://erewhon.superkuh.com/library/Neuroscience/Lipid%20Membrane/ http://erewhon.superkuh.com/library/Neuroscience/Lipid%20Mem...
- deleted 3y ago[deleted]