Decreased benzodiazepine receptor binding in Machado-Joseph disease.
Benzodiazepine receptor binding was assessed in four Japanese men with Machado-Joseph disease.


METHODS
The distribution of benzodiazepine receptors was measured by radionuclide imaging (SPECT) after intravenous administration of 123I-iomazenil (Ro 16-0154).


RESULTS
SPECT demonstrated decreased binding throughout the cerebral cortex and cerebellum in all patients. Binding potential (receptor concentration x affinity) was diffusely decreased in cerebral cortex, thalamus, striatum and cerebellum compared with control subjects, suggesting that GABAergic function may be decreased globally in these patients. Cerebral blood flow was largely normal, and no cerebral cortical atrophy was evident on MRI.


CONCLUSIONS
Iodine-123-iomazenil SPECT may become a potent method for detecting impairment of the cerebral cortex even before brain perfusion SPECT or MRI can reveal early abnormalities.
Ishibashi
M
M
Department of Radiology, Kurume University School of Medicine, Kurume-City, Fukuoka, Japan.
Sakai
T
T
Matsuishi
T
T
Yonekura
Y
Y
Yamashita
Y
Y
Abe
T
T
Ohnishi
Y
Y
Hayabuchi
N
N
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D016022:Case-Control Studies; D005442:Flumazenil / Q000031:analogs & derivatives*; D006801:Humans; D007457:Iodine Radioisotopes; D017827:Machado-Joseph Disease / Q000000981:diagnostic imaging* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D011963:Receptors, GABA-A / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D011963:Receptors, GABA-A; D005442:Flumazenil; C063038:iomazenil