BIOPHYSICAL AND BIOCHEMICAL STUDIES ON THE MICROSOMES OF NERVOUS TISSUES

In view of the fact that little attention has been paid to electron transfer system of brain microsomes, some studies have been made on microsomal cytochrome b5 and related oxidative activities and their relation to cation incorporation of brain microsomes. The results obtained strongly suggest the presence in neuronal elements of these cyanide- and antimycin-insensitive oxidative activities and a tentative formulation of electron transfer pathways in brain microsomes was presented. Some preliminary evidences for the view that cation incorporation in the brain microsomes is linked with the above-stated electron transfer system were obtained, but not yet conclusive. Using the light-scattering technique, it was demonstrated that the brain microsomes are capable of changing their shape or volume in vitro either passively by changes in the osmotic pressure of suspension medium or actively by ATP and Na or K ion. The questions as to whether Na and K dependent ATP-ase participates in such an active contraction of brain microsomes and whether electron transport through the cyanide-insensitive oxidative pathways is obligatory for microsomal contraction are now under investigations. (Author)