An elevated cadaverine content in the brain of dormant mice

Biosynthesis of 5-aminopentanoic acid and 2-piperidone from cadaverine and 1-piperideine in mouse

1-Piperideine, 5-aminopentanoic acid, and its lactam, 2-piperidone, were identified as metabolites of cadaverine in 10,000 g mouse liver supernatants to which diamine oxidase had been added. Both metabolites were also found when the cadaverine metabolite 1-piperideine was incubated with the preparation which suggested that 1-piperideine is an intermediate in the formation of 5-aminopentanoic acid and 2-piperidone. Identification of the metabolites was based on gas chromatography-mass spectrometric analysis in comparison to authentic standards. Mouse brain homogenates converted 1-piperideine to 5-aminopentanoic acid. The results suggest that the metabolic fate of cadaverine may provide precursors of pharmacologically active analogues of GABA.

Uptake, release, and metabolism of D- and L-alpha-aminoadipate by rat cerebral cortex

Accumulation of L-alpha-aminoadipate by rat cerebral cortical slices is a stereospecific and Na+-dependent process. The uptake of this compound is also temperature-dependent, with a Km of 1.6 X 10(-4)M for the high-affinity system. D-alpha-Aminoadipate has characteristics similar to those displayed by the L-isomer but to a lesser degree. L-Glutamate and L-aspartate inhibit the uptake of L-alpha-aminoadipate. D- and L-alpha-Aminoadipate are, respectively, weak uncompetitive and weak competitive inhibitors for the uptake of L-glutamate and L-aspartate. Both enantiomers inhibit GABA uptake but in quite different ways. The release of L-alpha-aminoadipate from the cerebral cortical slices is stimulated by a high concentration of K+ ions in the presence of Ca2+ in the perfusion buffer; the D-isomer displays this property to a lesser degree. The omission of Ca2+ markedly reduces the release of these two compounds. Less than 10% of the preloaded D- and L-alpha-aminoadipate are metabolized by the cerebral cortex during 40 min of superfusion. The possibility of L-alpha-aminoadipate as a neurotransmitter candidate is discussed.

Monoacylcadaverines in the blood of schizophrenic patients

Concentrations of cadaverine, monoacetylcadaverine and monopropionylcadaverine in the blood of schizophrenic and nonschizophrenic subjects were measured. Two groups, one from the U.S.A. the other from Japan, were tested. Monoacetylcadaverine and monopropionylcadaverine were found elevated in the blood of some schizophrenic patients in comparison with those in controls in each group. Their increase could be caused by a reduced monoamine oxidase activity or by an increased acylation in schizophrenic patients.

Metabolites of piperidine in rat urine

Piperidine is one of pharmacologically active biogenic amines. While two pathways for piperidine production have been reported, little is known about metabolism of the compound. In the present study, piperidine and its hydroxylated, conjugated and unknown metabolites were detected in rat urine by radiochromatographic analysis. Using GC-MS technique, it was confirmed that 3-hydroxypiperidine and 4-hydroxypiperidine are major metabolites of piperidine of either exogenous or endogenous origin. The findings substantiate the existence of a mechanism which inactivates piperidine in the living body, since both metabolites lack the potent pharmacological activities as those induced by piperidine.