High-affinity uptake of spermine by slices of rat cerebral cortex.
The accumulation of the polyamine spermine into 0.1-mm prisms of rat cerebral cortex has been investigated at both 37 percent C and at 4 percent C. Kinetic analysis of the temperature-sensitive portion of uptake indicates two high-affinity saturable components together with an unsaturable component at high concentrations. The "very high'-affinity saturable system (K(m)= 3.8 nM) was temperature- and sodium-dependent, and significantly reduced by metabolic inhibitors, finding that are consistent with an active transport system for spermine into brain tissue. The "high'-affinity saturable component (K(m)= 0.44 micron) was sodium-dependent and inhibited by ouabain, but only partially susceptible to inhibition by 2,4-dinitrophenol and sodium cyanide. The significance of these results with respect to the function of spermine in the central nervous system is discussed.
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D004140:Dinitrophenols / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D009994:Osmolar Concentration; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D012964:Sodium / Q000494:pharmacology; D012966:Sodium Cyanide / Q000494:pharmacology; D013096:Spermine / Q000378:metabolism*; D013696:Temperature
D004140:Dinitrophenols; D013096:Spermine; D010042:Ouabain; D012964:Sodium; D012966:Sodium Cyanide