Cerebral cortical calbindin D28K and parvalbumin neurones in Down's syndrome.

Anti-calbindin D28K (CaBP) and anti-parvalbumin (PVA) antibodies were used to study the number and size of neurones containing these two calcium binding proteins in post-mortem brains from 7 neurologically normal controls and from 4 elderly patients with clinically diagnosed Down's syndrome (DS) and whose brains contained numerous senile plaques and neurofibrillary tangles. The possible co-existence of these two calcium binding proteins in human cerebral cortex was also examined. In the controls, CaBP immunoreactive neurones were mainly non-pyramidal neurones although some pyramidal neurones were also CaBP immunoreactive. All the PVA immunoreactive neurones were non-pyramidal cells. CaBP and PVA did not apparently co-exist with each other in cortical neurones. When compared with the neurologically normal controls, the number and size of CaBP and PVA immunoreactive neurones were significantly reduced in the cortex of patients with DS. These findings show that CaBP and PVA containing cortical neurones are affected in elderly persons with DS.