Discrete regional distribution of biochemical markers for the dopamine, noradrenaline, serotonin, GABA and acetylcholine systems in the monkey brain (Cebus Apella). Effects of stress.

: Brains from Cebus Apella monkeys have been mapped biochemically using a cryo-section technique which enables exact micro-dissectioning of tissue. Two neurotransmitters; noradrenaline (NA) and gamma-amino-butyric acid (GABA) were measured by gas chromatography-masspectrometry technique. In addition biochemical markers reflecting metabolic activity in the dopamine (homovanillic acid, HVA, 3, 4-dihydroxyphenylacetic acid, DOPAC), serotonin (5-hydroxyindoleacetic acid, 5-HIAA), noradrenaline (4-hydroxy-3-methoxy-phenylglycol, HMPG), acetylcholine (choline acetyltransferase, CAT) and GABA (glutamic acid decarboxylase, GAD) transmitter systems were assayed. The distribution of these transmitter markers roughly corresponded to earlier studies in other non-human primates, whereas similar studies on the human brain generally show lower concentrations and enzyme activities. One monkey exposed to severe stress immediately before death deviated from the normal animals with regard to HVA, 5-HIAA, GAD and GABA. For the study of neuroleptic drugs, and notably their neurological side-effects, Cebus Apella monkeys have turned out to be particularly useful. In our laboratory we have employed this species of monkey to develop a model for acute dystonia and tardive dyskinesia (Gunne and Barany 1976, 1979, Barany et al. 1979). As a first step in the topological mapping of brain neuro-chemistry in these animals we here present data from normal monkeys, not treated with neuroleptics. During the ongoing project there was an unplanned "stress experiment" in one monkey, which had a nightly fight with a cage partner and had to be sacrificed the morning after due to severe wounds. The present communication describes a method for obtaining well-defined samples from monkey brains and presents the data on homovanillic acid (HVA), 3.4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindoleacetic acid (5-HIAA), noradrenaline (NA), 4-hydroxy-3-methoxy-phenyl glycol (HMPG), choline acetyltransferase (ChAT), glutamic acid decarboxylase (GAD), and gamma-amino-butyric acid (GABA) in discrete regions from 7 drug-naive control monkeys. Also data from the stressed animal are presented.