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PubMed1985

Electrochemical detection of biogenic amines following acylation by N-hydroxysuccinimide esters.

A general methodology for the selective derivatization of amines, to enable quantitation by high pressure liquid chromatography with electrochemical detection, is presented. N-Hydroxysuccinimide active esters present in large excess are suitably mild acylating agents to derivatize selectively trace quantities of amines for electrochemical detection. The 2 separate problems of extraction yield and detectability can be solved by this derivatization method. Due to its lipophilicity the resulting N-acylated amine, as demonstrated with serotonin, is extracted efficiently into organic solvents during sample preparation for chromatography. Moreover, the acyl group introduced can be designed to be electroactive, thus extending the procedure to amines not readily oxidized, e.g., histamine and phenylethylamine.

Acylation↗
PubMed1987

Distribution of biogenic amines and their catabolites in brains from patients with Alzheimer's disease.

Norepinephrine, epinephrine, dopamine, serotonin and their major catabolites were measured in 17 regions of the left hemisphere of two brains obtained from two brothers with Alzheimer's disease with very early onset. The clinical diagnosis was confirmed by histological examination of the right hemispheres and brain stems. The quantitative data were compared with our values in normal brains. In the patient suffering from the less severe dementia, there was a severe reduction of the serotonin concentration in all examined neocortical areas and its concentration was even below the detection limit in the nucleus amygdalis, hippocampus, caudate nucleus, putamen, globus pallidus and substantia nigra. In the other patient, who suffered from a more pronounced dementia with myoclonus, the serotonin concentration was below the detection limit in all examined structures. In contrast with these findings, the noradrenergic, adrenergic and dopaminergic systems appeared to be relatively unaffected by the disease process. Focusing our attention on the nuclei wherein the monoamine transmitter systems originate, it appeared that neuronal losses and neurofibrillary tangles clearly predominated in the substantia grisea subependymalis, the nucleus centralis superior and the nucleus raphe dorsalis, origin of the main serotonergic system. The serotonin deficiency sheds light on possible mechanisms of myoclonus in Alzheimer's disease.

Adult↗