High-Affinity Uptake of Spermine by Slices of Rat Cerebral Cortex |
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Authors: | R. J. Harman G. G. Shaw |
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Affiliation: | Department of Pharmacy, Pharmacology Laboratories, University of Nottingham, Nottingham, United Kingdom |
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Abstract: | Abstract: The accumulation of the polyamine spermine into 0.1-mm prisms of rat cerebral cortex has been investigated at both 37°C and at 4°C. Kinetic analysis of the temperature-sensitive portion of uptake indicates two high-aftinity 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, findings that are consistent with an active transport system for spermine into brain tissue. The 'high'– affinity saturable component ( K m= 0.44 μM) 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. |
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Keywords: | Spermine Polyamines Uptake Neuromodulator |
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