Nitric oxide synthase (NADPH-diaphorase) content in brain neurons of neonatal rats after inhibitory learning and intervention into nitric oxide metabolism.
Four-day-old rat pups were taught to avoid an electrified grid under the influence of increased nitric oxide availability in brain (by a nitric oxide substrate L-arginine) that alleviated learning or decreased nitric oxide (due to the action of a blocker of nitric oxide synthase nitro-L-arginine) that impaired learning. Three hours after criteria meeting, the pups were killed for analysis of nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase content in brain cells and neuropil. In the cingulate gyrus, NADPH-diaphorase-positive staining was increased after L-arginine, but an opposite picture was observed in hippocampus and basal ganglia, i.e. an increase after the blocker nitro-L-arginine. A noteworthy accumulation of NADPH-diaphorase in hippocampal cells might be tentatively explained by the blocking effect of nitro-L-arginine not allowing NADPH-diaphorase to leave the cells. Application of L-arginine or nitro-L-arginine provoked only minor changes in the studied structures of non-learned pups with the exception of hippocampus where nitro-L-arginine increased the width of neuropil, but to a lesser degree than in learned animals. These results clearly show that both manipulations, i.e. drug application and learning, only have a significant effect on the changes in NADPH-diaphorase positivity in brain neurons.
Petrovický
P
P
Institute of Anatomy, 1st Medical Faculty, Charles University Cz 120 00, Praha, Czech Republic.
Barcal
J
J
Myslivecek
J
J
D000818:Animals; D000831:Animals, Newborn; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D003342:Corpus Striatum / Q000502:physiology; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism*; D004597:Electroshock; D005917:Globus Pallidus / Q000502:physiology; D006179:Gyrus Cinguli / Q000502:physiology; D006624:Hippocampus / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D019335:Nitroarginine / Q000494:pharmacology*; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats
D019335:Nitroarginine; D019001:Nitric Oxide Synthase; D008058:Dihydrolipoamide Dehydrogenase