Brain glutamate uptake: Regional distribution study from sensorimotor areas in the cat

Regional distribution of glutamatergic activity was studied in the sensorimotor areas of the cat's brain, using microdissection of the structures and the high affinity glutamate uptake (HAGU) estimation as an index. For this purpose a procedure allowing the measurement of HAGU activity in sucrose homogenates of the microsamples dissected from refrigerated slices was developed. The highest glutamatergic activity was found in the ventral parts of the thalamus, followed by the caudate nucleus and the cerebral cortex. The mesencephalic structures showed the lowest glutamate (Glu) transport capacities among the regions of gray matter studied. Intranuclear investigations were carried out within the substantia nigra, the caudate nucleus and the red nucleus. Rostrocaudal variations in HAGU activity were shown within the red nucleus while no significant topographical variations were detected either in the substantia nigra or in the caudate nucleus.