Technically, I didn’t mentioned orexin, because I didn’t to get technical, but if I reminded you of it to some useful end, the you’re most welcome. People tend to start getting that eyes glazed over look by the time I mention the hypothalamus. I don’t know if Parkinsons works in a similar way, but narcolepsy has recently been found to be an autoimmune disorder that destroys orexin producing cells, that kind of makes sense to me because I have five other autoimmune disorders. I suppose that would be white blood cells attacking the brain rather than the neurons themselves if it’s autoimmune disease, wouldn’t it?
One would think that autoimmune problems that are Immunoglobulin related wouldn’t effect the CNS whereas if there were white cells involved it might but the barrier can be disrupted locally and allow large molecules to enter the CNS. I am not certain of the mechanisms of things like MS (is anybody) where you have macrophages EATING the myelin. But in the case of hypothalamic neurons it’s kind of hard to see how it could start if they were “normal”. I think with MS it is felt that there is an immunoglobulin that starts it and the white cells are just “cleaning up the debris” but I haven’t read on this subject in a long, long time.