Depending on the stability of your protein Triton-X114 might be helpful

If you add proper amount of Triton-X114 to your extraction buffer, it will separate above 22°C into two phases so that you will have in dense phase mainly membrane proteins which are not soluble in water while less dense phase will include less detergent and mostly water-soluble proteins

The traditional Jorgensen's method to isolate the Na-pump using SDS always works. However, my experience relates to isolation/purification from pig kidney and rat cardiac myocytes...not brain.