Influence of piperidine and pipecolic acid on the uptake of monoamines, GABA and glycine into P2 fractions of the rat brain and the spinal cord.

Abstract

Influence of piperidine and D, L-pipecolic acid, a hypnogenic amine and its possible precursor, on the uptake of L-[3H] noradrenaline (L-[3H] NA), [3H] dopamine ([3H] DA), [3H] 5-hydroxytryptamine ([3H] 5-HT), [14C] GABA and [14C] glycine into P2, fractions of the rat brain and the spinal cord was investigated. Neither piperidine nor D, L-pipecolic acid affected the uptake of L-[3H] NA, [3H] DA, [3H] 5-HT and [14C] glycine at a dose of 10-4M. On the other hand, D, L-pipecolic acid (10-4 M). significantly (p<0.01) inhibited the [14C] GABA uptake but not piperidine (10-4 M). These results suggest that a central cation of piperidine, e. g. sedation and sleep-prolongation, is not due to influence on the high affinity uptake mechanism of monoamines, GABA and glycine into synaptosomes in the central nervous system, and that pipecolic acid might interact with the GABA-ergic system as a neuromodulator.