Nicotinic alpha4beta2 receptor binding in dementia with Lewy bodies using 123I-5IA-85380 SPECT demonstrates a link between occipital changes and visual hallucinations.
BACKGROUND
To investigate in vivo differences in the distribution of alpha4beta2 subtypes of nAChR using the ligand (123)I-5-Iodo-3-[2(S)-2-azetidinylmethoxy] pyridine (5IA-85380) and single photon emission computed tomography (SPECT) in DLB and similarly aged controls.


METHODS
Thirty-one subjects (15 DLB and 16 controls) underwent (123)I-5IA-85380 and perfusion ((99m)Tc-exametazime) SPECT scanning. Patient scans were compared to scans of control subjects on a voxel-by-voxel basis using SPM2.


RESULTS
Compared to controls, significant reductions in relative (123)I-5IA-85380 uptake were identified in frontal, striatal, temporal and cingulate regions in DLB. Elevation of scaled (123)I-5IA-85380 uptake in occipital cortex was observed in DLB relative to controls, as well as being associated with DLB subjects with a recent history of visual hallucinations. Changes in (123)I-5IA-85380 SPECT in DLB were different from perfusion.


CONCLUSIONS
Reductions in normalised (123)I-5IA-85380 uptake in DLB were distinct from their perfusion deficits. Significant increase in occipital lobe uptake was present in DLB, a change most pronounced in subjects with a recent history of visual hallucinations. The findings directly link cholinergic changes in occipital lobe to visual hallucinations in DLB.
O'Brien
John T
JT
Institute for Ageing and Health, Newcastle University, Wolfson Research Centre, Newcastle General Hospital, Westgate Road, Newcastle upon Tyne NE4 6BE, UK.
Colloby
Sean J
SJ
Pakrasi
Sanjeet
S
Perry
Elaine K
EK
Pimlott
Sally L
SL
Wyper
David J
DJ
McKeith
Ian G
IG
Williams
E David
ED
D000368:Aged; D001384:Azetidines; D002074:Butanones; D005260:Female; D006212:Hallucinations / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020961:Lewy Body Disease / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008297:Male; D009483:Neuropsychological Tests; D009778:Occipital Lobe / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology*; D011725:Pyridines; D019275:Radiopharmaceuticals; D011978:Receptors, Nicotinic / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon
C426745:5-iodo-3-(2-azetidinylmethoxy)pyridine; D001384:Azetidines; D002074:Butanones; D011725:Pyridines; D019275:Radiopharmaceuticals; D011978:Receptors, Nicotinic; C403531:nicotinic receptor alpha4beta2; C078058:exametazime