Abstract
Activities of tyrosine hydroxylase (TH), aromatic amino acid decarboxylase (AD), dopamine-β-hydroxylase (DH), monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) were studied in various areas of human brains obtained at autopsy. The use of autopsy material seemed justified since activities of these five enzymes remained unchanged in brains of rats which had been killed by cervical dislocation and had been stored for 16 hr at either 4°C or 20°C. COMT (dihydroxybenzoic acid as substrate) activities were uniformly distributed among the areas studied. MAO (tryptamine) activities were usually high in the hypothalamus, head of caudatus and substantia nigra and low in the cerebral and cerebellar cortices, pons and thalamus. High DH (dopamine) activities were most frequently found in the globus pallidus, substantia nigra and hypothalamus, whereas low activities were observed in the cerebellar cortex and head of caudatus. TH (tyrosine) activities were low and in many samples even below the sensitivity of the method. AD (5-hydroxytryptophan) activities could not be detected in the human brain areas studied and, if present, were below the sensitivity of the method used. All enzyme activities observed showed a reasonably similar pattern of distribution, as found in the brains of some animal species. A comparison of identical areas obtained from different individuals revealed that activities of DH, MAO and TH varied markedly in some areas but were almost identical in other areas; no marked variations of COMT activities were observed.
Footnotes
- Received July 1, 1968.
- Accepted October 29, 1968.
- © 1969 by The Williams & Wilkins Co.
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