Ispectrum Magazine Ispectrum Magazine #06 - Page 31

The Glial Cell and Incipient Dementia Short Circuiting the Brain. The human brain has never before been presented with chronic excess energy in the circulation – its evolutionary history is one of exposure to food and energy famine. The brain is highly efficient at preserving its energy supply during energy famines or starvation (as in anorexia nervosa), but has not evolved sophisticated mechanisms to deal with chronic systemic energy excess – it simply suppresses energy income and triggers a protracted short circuit (chronic/not acute). The key to understanding a range of modern metabolic diseases, both physiological and neurological, is to be found in the glial cell. That is to say that this cell, for which there are around 6 for every neurone, is ground zero in obesity/diabetes/ cardiovascular disease and a variety of neurological conditions such as Alzheimer’s disease/motor neurone disease/Parkinson’s disease and multiple sclerosis. The human brain affords the highest rate of energy consumption known in nature. Indeed on a like for like basis the human brain consumes 22 times the energy of a muscle cell (The Expensive Tissue Hypothesis). At any moment there is only around 1 gram of glucose in the brain – sufficient for only a few minutes. The circulation carries only 5 grams so a fall in blood glucose concentration (hypoglycaemia) is catastrophic for the brain and will rapidly lead to a coma, if not reversed. The cerebral glucose pump – the glutamate/glu30