title: Variations in the activTY OF SOME BRAIN AND PLASMA ENZYMES UNDER THE INFLUENCE OF +Gz acceleration.
abstract: The present paper refers to the activity of some enzymes associated with the cellular cytomembranes in the plasma and brain of guinea pigs exposed to the action of repeated +10Gz acceleration. Immediately after the last run, diminution of enzymatic activity in the brain supernate ran parralel to a rise in plasma enzymatic activity. Variations in enzymatic activity suggested the liberation of enzymes connected with the neuronal organelles, perhaps consequent to alterations in the permeability or structure of the neuronal cytomembranes. These alterations might also be interpreted as being accompanied by permeabilization of the blood-brain barrier, with release of enzymes from the neuronal structures into the plasma. Changes in the permeability of the neuronal membranes might be attributed to several factors: cerebral hypoxia following the hemodynamic and ventilation alterations induced by hypergravitation, the influence upon the membrane permeability of hormones released in excess under the stress of acceleration, and the strain to which the central nervous system neurones are subjected by the multitude of afferent impulses with a starting point in the various types of receptors stimulated by hypergravitation.
mesh_terms: D000054:Acceleration; D000135:Acid Phosphatase / Q000097:blood / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000097:blood / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology*; D001923:Brain Chemistry; D002540:Cerebral Cortex / Q000166:cytology; D005954:Glucosephosphate Dehydrogenase / Q000097:blood / Q000378:metabolism*; D006112:Gravitation; D006168:Guinea Pigs; D007770:L-Lactate Dehydrogenase / Q000097:blood / Q000378:metabolism*; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000648:ultrastructure; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011506:Proteins / Q000032:analysis
chemical_list: D011506:Proteins; D007770:L-Lactate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D010744:Phosphoric Monoester Hydrolases