DECREASED NUMBER OF OXYTOCIN-IMMUNOREACTIVE NEURONS IN THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS IN PARKINSONS-DISEASE

We determined the number of immunocytochemically identified oxytocin ( OXT) and vasopressin (AVP) neurons in the paraventricular nucleus (PVN ) of the human hypothalamus of six Parkinson's disease (PD) patients r anging from 59 to 83 years of age. Six subjects without a primary neur ologic or psychiatric disease, ranging from 69 to 88 years of age, ser ved as controls. The OXT-immunoreactive cell number in the PVN of the PD patients was 22% lower than that of the control subjects. Although Lewy bodies were present in the nucleus basalis of Meynert, there were no Lewy bodies in the PVN of these patients. Doubt is raised about th e presumed direct relationship between the presence of Lewy bodies and neuronal degeneration in PD. The AVP-immunoreactive cell number in th e PD patients showed a similar decreasing trend, but the 18% reduction failed to reach statistical significance. The presence of tyrosine hy droxylase-positive neurons in the PVN was not affected in PD patients, supporting the notion that dopaminergic neurons of the mesencephalon, but not of the hypothalamus, are affected in PD. The decreased number of OXT-containing neurons in the PVN suggests that dopamine may be im portant for the function of these neurons and may provide a neural bas is for some autonomic and endocrine disturbances in PD.