CALBINDIN-D-28K-CONTAINING NEURONS IN THE HUMAN HYPOTHALAMUS - RELATIONSHIP TO DOPAMINERGIC-NEURONS

Calbindin-D-28k is a calcium-binding protein that protects nerve cells from degeneration. It is located in the midbrain dopaminergic neurons that are relatively invulnerable to degeneration in Parkinson's disea se. Because the hypothalamic dopaminergic neurons do not degenerate in Parkinson's disease, the present study sought to determine whether th ese neurons also contain calbindin-D-28k. Using immunocytochemical sta ining with antibodies against calbindin-D-28k and tyrosine hydroxylase , and computer imaging techniques, the distributions of calbindin-D-28 k and tyrosine hydroxylase-containing neurons were mapped. Both neuron al populations were present throughout the rostral-caudal extent of th e hypothalamus. However, only in the periventricular region, at the pr eoptic and anterior hypothalamic levels, was there an overlap in the t wo cellular distributions. Using the presence of neuromelanin pigment as a marker for dopaminergic neurons, approximately 30% of the dopamin ergic neurons contain calbindin-D-28k in the periventricular region. T hese data indicate that a sub-population of hypothalamic dopaminergic neurons contain calbindin-D-28k. This finding is discussed in terms of why hypothalamic dopaminergic neurons are resistant to degeneration i n Parkinson's disease. (C) 1995 Academic Press Limited.