Electrical conductivity, brain tissues

Since brain tissue has conducting properties, while the air and skuU are almost complete insulators, the vector potential will induce accumulation of electric charge at the brain surface. This charge is another source for electric field, which can be expressed as ... 

During Amy Lloyd s evalnation, she developed a cardiac arrhythmia that was refractory to treatment. The extensive amyloid deposits in her heart had disrupted conduction of electrical impulses in the heart muscle, ultimately resulting in cardiac arrest. On autopsy, amyloid deposits were found within the heart, tongue, liver, adipose tissue, and every organ examined except the central nervous system, which had been protected by the blood-brain barrier. 

The sodium channel consists of various subunits, depending on the tissue of origin. The ot subunit is the major and most important component because expression of the a subunits of brain or skeletal muscle sodium channels in Xenopus oocytes without the p subunits yields functional sodium channels, although these are activated and inactivated more slowly than the sodium channels in native neuron or muscle. Only when coexpressed with pi and p2 subunits, normal channel gating is observed (Isom et al, 1992, 1995 Schreibmayer et al, 1994). The channel from mannalian brain is a complex of an a subunit (260 kDa), a pi subunit (36 kDa), and a p2 subunit (33 kDa). The channel from skeletal muscle contains only the a and pi subunits in the channel from electric eel electroplax, only the a subunit is required for ion conductance. 

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