Fig. 3

Effect of isoproterenol and serotonin on the state of phosphorylation of Na⁺,K⁺-ATPase in choroid plexus. Phosphorylation of Na⁺,K⁺-ATPase was measured as incorporation of radioactivity into the protein after stimulation of ³²P-labeled choroid plexuses for 10 min at 30°C in the absence or presence of 10 µM isoproterenol (Isopr) and 10 µM serotonin (5-HT). (A) Autoradiogram obtained after immunoprecipitation of Na⁺,K⁺-ATPase and separation by SDS-PAGE, showing the incorporation of ³²P into Na⁺,K⁺-ATPase in a typical experiment. (B) Quantitative analysis of Na⁺,K⁺-ATPase phosphorylation determined in three experiments (data represent means ± S.E.M.); **p < 0.01 vs. control. Student’s t test.