Autoradiographic distribution of binding sites for the non-NMDA receptor antagonist [3H]CNQX in human motor cortex, brainstem and spinal cord.
The distribution of non-NMDA receptors in the normal human motor cortex, brainstem and spinal cord has been investigated using [3H]CNQX. In the motor and premotor cortex, specific [3H]CNQX binding was present in all cortical laminae with the highest density of binding sites in laminae I, II and the upper part of III. In the normal brainstem, non-NMDA receptors labelled by [3H]CNQX had a heterogeneous distribution. Brainstem motor nuclei subserving eye movements, which tend to be spared in motor neuron disease (MND), had a higher density of [3H]CNQX binding sites compared to other cranial nerve motor nuclei (VII, X, XII) which tend to be affected. Specific [3H]CNQX binding was present throughout the spinal grey matter, the greatest density of binding being found in the substantia gelatinosa. Excitotoxicity at non-NMDA receptors has been implicated in chronic neurodegenerative diseases such as motor neuron disease. This study suggests that the density of non-NMDA receptors, labelled by [3H]CNQX, does not account for selective vulnerability of motor neurons in this disorder.
Chinnery
R M
RM
Department of Clinical Neurosciences, University of Newcastle upon Tyne, UK.
Shaw
P J
PJ
Ince
P G
PG
Johnson
M
M
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000368:Aged; D001345:Autoradiography; D001665:Binding Sites / Q000502:physiology; D001933:Brain Stem / Q000737:chemistry*; D005260:Female; D006801:Humans; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000737:chemistry*; D009333:Neck; D011810:Quinoxalines / Q000378:metabolism*; D011869:Radioligand Assay; D013116:Spinal Cord / Q000737:chemistry*; D014316:Tritium
D011810:Quinoxalines; D014316:Tritium; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione