PARVALBUMIN AND CALBINDIN D-28K IN THE HUMAN MOTOR SYSTEM AND IN MOTOR-NEURON DISEASE

Calbindin D-28k and parvalbumin are neuronal calcium binding proteins of interest in relation to neurodegenerative diseases. Expression of c albindin and parvalbumin may be one of the determinants of selective v ulnerability in these disorders. The distribution of these proteins wa s surveyed in the normal human motor system and in motor neuron diseas e (MND) using immunocytochemistry in formalin fixed post-mortem tissue s. CNS tissues from 14 MND patients (mean age 61.2 years, mean post-mo rtem delay 24.6 h) and seven controls (mean age 62.6 years, mean post- mortem delay 2 5.3 h) were studied. Preliminary studies on the effects of fixation were performed. In normal cases upper and lower motor neu rons showed absent expression of both proteins. Several neuronal group s characteristically spared in MND showed varying patterns of immunore activity: oculo-motor neurons showed parvalbumin staining of the perik aryon; the thoracic preganglionic sympathetic neurons showed calbindin staining in perikarya, Onuf's nucleus showed calbindin staining in th e neuropil only. In motor neuron disease a loss of ventral horn intern eurons and calbindin immunoreactive processes was observed with no oth er disease related changes in the spinal cord, brain-stem, or motor co rtex. These findings are consistent with the hypothesis that the distr ibution of these proteins is one determinant of selective vulnerabilit y to the neurodegenerative processes in MND acting via disturbance of neuronal calcium homeostasis.