CHOLINERGIC TRANSMITTER AND NEUROTROPHIC ACTIVITIES IN LEWY BODY DEMENTIA - SIMILARITY TO PARKINSON AND DISTINCTION FROM ALZHEIMER-DISEASE

Senile dementia of Lewy body type or Lewy body dementia (LBD), charact erized neuropathologically by the presence of Lewy bodies in the brain stem and cortex, and in most cases neocortical senile plaques (but few or no tangles), bears a closer resemblance to Parkinson's (PD) than t o Alzheimer disease (AD) in its cholinergic neurochemical pathology. T hus, reductions in the biochemical activity of choline acetyltransfera se were generally more extensive in neo- as opposed to archicortical r egions in LBD (especially hallucinating cases) and in PD, whereas musc arinic receptor binding was significantly increased in LBD and PD but not in AD. Nerve growth factor receptor (P75) assessed immunocytochemi cally in the archicortex were decreased in PD and, to a lesser extent, in LBD in conjunction with reductions of neuronal numbers in the nucl eus of Meynert (Ch4), but were relatively spared in AD. These observat ions indicate that although AD is primarily associated with dysfunctio n of cholinergic axonal input to the cortex, LBD and PD are more likel y to involve degeneration of the basal forebrain cholinergic system. R elevance of the findings in terms of aetiopathology and cholinergic tr eatment strategies is discussed.