NORADRENALINE, DOPAMINE AND SEROTONIN LEVELS AND METABOLISM IN THE HUMAN HYPOTHALAMUS - OBSERVATIONS IN PARKINSONS-DISEASE AND NORMAL SUBJECTS

In order to determine whether, besides the severe striatal dopamine (D A) loss, other brain neurotransmitter changes may be a constant bioche mical feature of idiopathic Parkinson's disease (iPD), we measured the concentration of the three major brain monoamines noradrenaline (NA), DA, and serotonin (5-HT) and their metabolites in five rostro-caudal subdivisions of the hypothalamus of eight control patients and nine pa tients with morphologically confirmed iPD. In the whole hypothalamus o f the iPD patients we found a mild to moderate mean reduction of NA (- 52%, P < 0.05), DA (-25%), and 5-HT (-26%). At the subregional level, the most consistently affected area was the intermediate subdivision o f the hypothalamus proper where all three monoamines were statisticall y significantly reduced. Evaluation of individual patient values indic ated that, in contrast to the constant and severe DA reduction present in putamen of each of the iPD patients (DA loss ranging from 96% to 9 9%), several of these patients had whole (and subregional) hypothalami c monoamine values well within the range of controls. We conclude that , although possibly involved in autonomic and/or endocrine disturbance s in some patients with iPD, none of the observed monoamine changes in the hypothalamus is an obligatory feature of iPD. Our study demonstra tes the need for evaluation of individual patient values rather than m ean differences in order to permit valid conclusions to be drawn as to whether an observed neurochemical change can be regarded as specific to a given brain disorder.