Effect of Sleep Deprivation And Alzheimer’s Disease
A team of scientists led by a UC Berkeley researcher has linked persistent poor sleep to the buildup of a toxic protein that can inhibit the ability to form long-term memory and eventually lead to the onset of Alzheimer’s disease.
Plaques of beta-amyloid, which have been associated with symptoms of Alzheimer’s, block the transmission of memory from the hippocampus — a region of the brain associated with encoding short-term memories into long-term ones — to the prefrontal cortex, a region associated with long-term, episodic memory.
“Sleep was the missing link between memory, Alzheimer’s and beta-amyloid,” said Vikram Rao, a researcher involved in the study.
Sleep loss increases the risk of Alzheimer’s disease, and disrupted sleeping patterns are among the first signs of this devastating disorder. One of the hallmarks of Alzheimer’s disease is a broken cellular clock – often marked by the inability to distinguish between night and day.
Researchers used mice to test whether injecting salt into the brain enables control of the mouse’s sleep-wake cycle—independently. The study shows that adrenaline and other neuromodulators change the level of salts surrounding the neurons and that the salt balance then decides whether the neurons are sensitive to stimulation in the shape of a touch. When we are awake, the salt balance makes neurons highly sensitive to stimulation, as opposed to the salt balance in the brain during sleep, where the level of salts makes it harder to activate the neurons.
When there is adequate sodium in the extracellular fluid, the continuous inward movement of sodium ions into the resting cell activates an enzyme. This enzyme – sodium-potassium ATPase, causes ATP to break down into ADP and phosphate. This breakdown stimulates the consumption of fuel and oxygen to maintain an adequate level of ATP. Increasing the concentration of sodium increases the energy consumption and carbon dioxide production of the cell. The sodium, by increasing carbon dioxide production, protects against the excitatory, toxic effects of the intracellular calcium.
In the Alzheimer’s patient, levels of adrenaline, cortisol, prolactin and estrogen are often high. These hormones are known to be exito-toxic to the brain (stimulate the brain inappropriately). High levels of these hormones contribute to the agitation and anxiety that is common in those with Alzheimer’s. In many cases the excess of estrogen will lead to masculinization of women. You will notice many women with alzheimer’s have a lot of facial hair. Cortisol slows down the cells ability to carry out normal functions e.g, calcium, magnesuim and potassium regulation. As a result, calcium increases inside the cells. Increase in calcium in the mitochondria is closely associated with its ability to increase intracellular calcium. Cortisol blocks the thermogenic (heat producing) effects of sodium. This is why many elderly are often cold, and why calcification of tissues is a key factor in aging an death.
Why The Healthy Brain Needs Salt
A lack of sodium slows metabolism, lowers carbon dioxide production, and creates inflammation, stress and degeneration. Protein, salt, thyroid, and progesterone happen to be thermogenic, increasing heat production and stabilizing body temperature at a higher level. – Ray Peat PhD.,
Activation of heat production and increased body temperature might account for some of the GABA-like sedative effects of increased sodium. Increasing GABA in the brain increases brown fat heat production (Horton, et al., 1988). Activation of heat production by brown fat increases slow wave sleep (Dewasmes, et al., 2003), the loss of which is characteristic of aging. (In adult humans, the skeletal muscles have heat-producing functions similar to brown fat.)
It is clear that when it comes to sleep deprivation and alzheimer’s disease, salt plays a vital role in the well being of the brain. When you consider that the healthy brain needs 7-8 hours of uninterrupted sleep, one cannot afford to skimp on sleep. It should also be noted that during sleep hours the body cleanses the brain of the amyloid plaques that are hallmark of Alzheimer’s disease!
See Dr. Ray Peat For more On Salt, Energy and Metabolic Rate And Longevity