The stability of 5-hydroxyindoleacetic acid and noradrenaline in normal and Alzheimer post mortem brain

Abstract

of Huntington and Parkinson (Bernheimer et al., 1973; Spokes, 1980). Because of the post mortem instability of biosynthetic marker enzymes, such studies have relied upon determination of the concentration of transmitter amines and their metabolites. By contrast, there have been few similar studies of cortical regions, largely because of the relatively low concentrations of the transmitters and some of their metabolites. The present study takes advantage of recent advances in h.p.1.c. technology in order to measure neocortical concentrations of 5hydroxytryptamine (5-HT) and noradrenaline (NA) and their major metabolites, 5-hydroxyindoleacetic acid (5HIAA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) respectively. The post mortem stability of these compounds has been examined by comparing the concentrations in tissue obtained post mortem and during life. Tissue from the fronto-temporal lobes was obtained at neurosurgery, as previously described (Sims et al., 1981), from 79 patients (aged 8-74 years) undergoing treatment for tumours or aneurysm, where the removal of apparently normal tissue was a necessary part of the surgical procedure. Tissue from the same lobes was obtained post mortem from 34 subjects (aged 38-99 years; postmortem delay 4-72 h) free of neurological or psychiatric illness, as described elsewhere (Francis et al., 1985). All samples were stored frozen (70°C or less) and neurosurgical tissue (30-60 mg) and post mortem tissue (1 00-200 mg) homogenized in acid (1 M-acetic acid for MHPG and 0.4 M-perchloric acid for all other compounds) containing 1 mwcysteine and I ~ M E D T A together with an appropriate internal standard (3,4-dihydroxybenzylamine, a-methyldopamine or vanillic acid). After centriof many studies, most nota ! ly with regard to the diseases