title: Cortical neuropathological and neurochemical substrates of Alzheimer's and Parkinson's diseases.
abstract: Whilst the neuropathological correlates of Alzheimer type dementia--cortical neurofibrillary tangles and senile plaques--are well defined, the prevalence of these cortical abnormalities in Parkinson's disease and their relation to dementia is unclear. In a series of 46 consecutive cases of clinically and pathologically established Parkinson's disease the prevalence of mild Alzheimer-type pathology (exceeding the normal but not as extensive as in Alzheimer's disease) was increased 2 to 3 fold compared with an age-matched control group, although there was no obvious relation to the presence or severity of dementia. In a subgroup of Parkinsonian cases (both demented and non-demented), examined neurochemically, there were both similarities (decreased choline acetyltransferase, nicotinic and serotonergic S 1 receptor activities) and distinctions (increased muscarinic receptor binding--particularly to the "L" subtype, and normal serotonergic S 2, somatostatin, and D-aspartate binding together with normal levels of an endogenous nicotine binding inhibitor) compared with a group of cases with Alzheimer's disease. Amongst the various pathological and chemical indices examined, only presynaptic cholinergic markers (including the number of Meynert neurons) and S 1 receptor binding were related to dementia in Parkinson's disease. It is suggested that whilst coincidental classical Alzheimer's disease is infrequent in Parkinson's disease (5% in the present series) Alzheimer's disease itself is distinguished from Parkinson's disease by the formation of numerous neocortical neurofibrillary tangles and a reduction in glutamate uptake, serotonergic S 2 receptors and possibly in endogenous nicotine binding inhibitor.
authors.affiliation: Department of Neuropathology, Newcastle General Hospital, Newcastle upon Tyne.
authors.forename: R H
authors.initials: RH
authors.lastname: Perry
authors.forename: E K
authors.initials: EK
authors.lastname: Perry
authors.forename: C J
authors.initials: CJ
authors.lastname: Smith
authors.forename: J H
authors.initials: JH
authors.lastname: Xuereb
authors.forename: D
authors.initials: D
authors.lastname: Irving
authors.forename: C A
authors.initials: CA
authors.lastname: Whitford
authors.forename: J M
authors.initials: JM
authors.lastname: Candy
authors.forename: A J
authors.initials: AJ
authors.lastname: Cross
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000378:metabolism*; D011950:Receptors, Cholinergic / Q000378:metabolism; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000378:metabolism
chemical_list: D011950:Receptors, Cholinergic; D017981:Receptors, Neurotransmitter; D011985:Receptors, Serotonin