Cerebral ammonia levels and enzyme changes during Plasmodium yoelii infection in mice.
Ammonia, lactate and glutamate levels and the activities of glutamine synthetase (GS), glutamate dehydrogenase (GDH), glutaminase (GLN), aspartate transaminase (AST), phosphofructokinase (PFK) and monoamine oxidase (MAO) were compared in the brain tissue of normal and P. yoelii infected mice. The brain lactate increased by 96% at peak parasitaemia. Cerebral ammonia also exhibited an increase in infected mice which was parasitaemia dependent, while glutamate remained almost unchanged. The brain glutamine synthetase registered an increase of 35% (P < 0.001) in post-mitochondrial fractions, this effect being perceptible even at low parasitaemia, but attained constancy at parasitaemia levels higher than 20%. The activity of monoamine oxidase and phosphofructokinase increased by 105% (P < 0.02) and 41% (P < 0.05) respectively while glutamate dehydrogenase decreased by 15% (P < 0.001). Glutaminase and aspartate transaminase were not significantly influenced by infection (tested only at high parasitaemia levels). It has been postulated that cerebral hypoxia and aberrations in ammonia metabolism may both contribute towards malaria induced cerebral complications.
Division of Biochemistry, Central Drug Research Institute, Lucknow, India.
M C
MC
Sharma
L M
LM
Tripathi
P
P
Sagar
G P
GP
Dutta
V C
VC
Pandey
D000641:Ammonia / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D001219:Aspartate Aminotransferases / Q000032:analysis; D001921:Brain / Q000201:enzymology*; D001923:Brain Chemistry; D005969:Glutamate Dehydrogenase / Q000032:analysis; D005974:Glutamate-Ammonia Ligase / Q000032:analysis; D005971:Glutamates / Q000032:analysis; D005972:Glutaminase / Q000032:analysis; D007773:Lactates / Q000032:analysis; D008288:Malaria / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D008995:Monoamine Oxidase / Q000032:analysis; D010732:Phosphofructokinase-1 / Q000032:analysis; D010967:Plasmodium yoelii
D005971:Glutamates; D007773:Lactates; D000641:Ammonia; D005969:Glutamate Dehydrogenase; D008995:Monoamine Oxidase; D001219:Aspartate Aminotransferases; D010732:Phosphofructokinase-1; D005972:Glutaminase; D005974:Glutamate-Ammonia Ligase