Brain (Na+,K+)-ATPase and noradrenergic function: recovery of enzyme activity after norepinephrine depletion.
We examined the time course of K+-p-nitrophenylphosphatase and ouabain binding associated with cerebral cortex (Na+,K+)-AT-Pase after depletion of norepinephrine. Norepinephrine depletion by the norepinephrine-selective neurotoxin DSP4 initially reduced the indices of (Na+,K+)-ATPase, with a significant correlation between ouabain binding and tissue norepinephrine levels 16 h after DSP4. Tissue norepinephrine content and DMI binding rapidly declined after DSP4 and remained essentially unchanged for at least 8 weeks. By contrast, the indices of (Na+,K+)-ATPase remained low for about two weeks but then gradually increased, returning to baseline levels by 8 weeks after DSP4. These data indicate that, while usually regulated in part by exposure to norepinephrine, brain (Na+,K+)-ATPase undergoes adaptation to prolonged noradrenergic depletion.
D009597:4-Nitrophenylphosphatase / Q000378:metabolism; D000588:Amines / Q000494:pharmacology*; D000818:Animals; D001596:Benzylamines / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000201:enzymology / Q000502:physiology*; D008297:Male; D009638:Norepinephrine / Q000502:physiology*; D010042:Ouabain / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D000588:Amines; D001596:Benzylamines; D010042:Ouabain; D009597:4-Nitrophenylphosphatase; D000254:Sodium-Potassium-Exchanging ATPase; C012102:DSP 4; D009638:Norepinephrine