Uptake of piperidine and pipecolic acid by synaptosomes from mouse brain.
Piperidine is actively transported into the synaptosomal fraction of adult mouse brain. The transport mechanism appears to be Na+ independent but is temperature dependent and sensitive to ouabain. Analysis of kinetic experiments indicates only a "low-affinity" transport system to be present. By contrast the uptake of D,L-[(3)H]pipecolic acid at a concentration of 4 X 10(-7)M was temperature and Na+ dependent, ouabain sensitive, and revealed a two-component system with a Km = 3.9 plus or minus 0.17 X 10(-6)M, Vmax = 129 plus or minus 6 pmol/mg protein/3 min for the "high-affinity" system and a Km = 90.2 plus or minus 4.3 X 10 (-6)M, Vmax = 2.45 plus or minus 0.19 nmol/mg protein/3 min for the "low-affinity" system. Compounds structurally related to pipecolic acid such as glycine, L-proline, 4-amino-n-butyric acid, and 5-amino-n-valeric acid showed an inhibitory effect on uptake at a concentration of 10(-4)M. The demonstration of biosynthesis of pipecolic acid in mouse brain and the presence of a "high-affinity" sodium-dependent uptake system suggest a physiological role of this substance in the central nervous system.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010042:Ouabain / Q000494:pharmacology; D010875:Pipecolic Acids / Q000096:biosynthesis / Q000378:metabolism*; D010880:Piperidines / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013574:Synaptosomes / Q000378:metabolism
D010875:Pipecolic Acids; D010880:Piperidines; D010042:Ouabain; D012964:Sodium