Margaret A Piggott

..Dementia developing late in the course of PD shares many of the same clinical and pathological characteristics...

..D2 receptor binding did not vary with cognitive decline (MMSE) or visual hallucinations, but was significantly higher with increased extrapyramidal symptoms...

..The distinct changes in the rostrocaudal pattern of expression of dopaminergic parameters are relevant to the interpretation of the in vivo imaging and diagnosis of DLB...

..That the reduction of D2 receptors correlated with cognitive decline suggests that neuroleptics, as dopamine D2 receptor antagonists, may have a deleterious effect on cognition in DLB...

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..Low density of striatal M1 receptors may relate to the extent of movement disorder in DLB, and to a reduced risk of parkinsonism with acetylcholinesterase inhibition...

..Upregulation of M2 and M4 muscarinic receptors in cingulate and adjacent cortex may thus contribute to the development of psychosis in DLB, with potential implications for treatments with drugs acting on these receptors...

..We conclude from this first systematic study of cortical muscarinic receptors in PSP that functioning cortical muscarinic receptors are preserved. A further, larger trial of cholinergic therapy, such as an M1 agonist, may be warranted...

..These results do not account for the poor response to dopaminergic and cholinergic replacement therapies in PSP, and suggest relative preservation of postsynaptic striatal projection neurones bearing D2/M1 receptors...

..123I-QNB binding was also compared to the corresponding cerebral perfusion changes in the same subjects...

..There were no significant changes in the ventrolateral nucleus (motor). Cholinergic dysfunction within the AP and MD nuclei of the thalamus may contribute to behavioral and cognitive disturbances associated with PSP...

..Cholinergic deficits based on clinical and neurochemical parameters are then discussed, before concluding with suggested future directions for cholinergic treatments...

..In DLB + EPF and PD patients, there was decreased binding in the ventral lateral nucleus. This study demonstrates alterations of alpha6 and/or alpha3 nAChRs binding in DLB and PD, which are likely to relate to extra-pyramidal symptoms...

..001). Loss of cortical alpha 7 nicotinic receptors may contribute to hallucinations and delusional misidentification in DLB, with implications for treatment and understanding the mechanisms of psychotic symptoms in dementia...

..Further study is warranted to explore which nicotinic receptor subunits and which neuronal compartments are involved in the changes in [3H]nicotine binding reported, to aid development of potential nicotinic receptor therapy...

..These data suggest that H3-receptors are present upon striatonigral projection neurons of the direct and indirect movement pathways thus providing histaminergic control over the activity of both these circuits...

..This relates, in part, to a lack of knowledge of the underlying neurochemical abnormalities, including cholinergic receptor status in the basal ganglia...