ISSN:
1619-7089
Keywords:
Benzodiazepine receptor
;
GABAA receptor
;
Angelman syndrome
;
Iodine-123 iomazenil
;
Cerebral blood flow
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract A receptor mapping technique using iodine-123 iomazenil and single-photon emission tomography (SPET) was employed to examine benzodiazepine receptor binding in a patient with Angelman syndrome (AS). AS is characterized by developmental delay, seizures, inappropriate laughter and ataxic movement. In this entity there is a cytogenic deletion of the proximal long arm of chromosome 15g11–q13, where the gene encoding the GABAA receptorβ3 subunit (GABRB3) is located. Since the benzodiazepine receptor is constructed as a receptor-ionophore complex that contains the GABAA receptor, it is a suitable marker for GABA-ergic synapsis. To determine whether benzodiazepine receptor density, which indirectly indicates changes in GABAA receptor density, is altered in the brain in patients with AS, we investigated a 27-year-old woman with AS using123I-iomazenil and SPET. Receptor density was quantitatively assessed by measuring the binding potential using a simplified method. Regional cerebral blood flow was also measured withN-isopropyl-p-[123I]iodoamphetamine. We demonstrated that benzodiazepine receptor density is severely decreased in the cerebellum, and mildly decreased in the frontal and temporal cortices and basal ganglia, a result which is considered to indicate decreased GABAA receptor density in these regions. Although the deletion of GABRB3 was not observed in the present study, we indirectly demonstrated the disturbance of inhibitory neurotransmission mediated by the GABAA receptor in the investigated patient.123I-iomazenil with SPET was useful to map benzodiazepine receptors, which indicate GABAA receptor distribution and their density.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00833400
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