This is an historical archive of the activities of the MRC Anatomical Neuropharmacology Unit (MRC ANU) that operated at the University of Oxford from 1985 until March 2015. The MRC ANU established a reputation for world-leading research on the brain, for training new generations of scientists, and for engaging the general public in neuroscience. The successes of the MRC ANU are now built upon at the MRC Brain Network Dynamics Unit at the University of Oxford.

Synapses, axonal and dendritic patterns of GABA-immunoreactive neurons in human cerebral cortex.

Brain 1990;113 ( Pt 3)():793-812.

Synapses, axonal and dendritic patterns of GABA-immunoreactive neurons in human cerebral cortex.

Kisvárday ZF, Gulyas A, Beroukas D, North JB, Chubb IW, Somogyi P
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Abstract:
Gamma-aminobutyric acid (GABA) containing neurons were characterized in human association cortex by a combination of Golgi impregnation and immunohistochemistry. Neurons were Golgi impregnated, gold toned, drawn and then classified on the basis of their dendritic and axonal arborization in layers I-VI. An antiserum to GABA was used to determine which of the impregnated neurons were immunopositive. Twenty-four GABA-positive cells were Golgi impregnated: 7 were bitufted with their dendrites predominantly radially oriented, and 17 were multipolar stellate cells. Three of the multipolar cells with large somata in the deep layers showed dendritic patterns similar to previously described basket cells. Nine of the multipolar stellate cells in layers III-VI showed characteristics of 'neurogliaform' neurons (Ramón y Cajal, 1899). The somata and the dendritic field of these cells were spherical, with diameters of about 10-15 microns and 200 microns, respectively. Their dendrites were smooth and slightly beaded. The axon collaterals were densely distributed in and around the dendritic field, in a spherical area with a diameter of at least 300 microns. The thin axon collaterals had only occasional 'en passant' swellings. Contacts between the axons of neurogliaform cells and the distal dendrites of Golgi-impregnated pyramidal cells were observed. Electron microscopic immunocytochemistry revealed that GABA immunopositive nerve terminals formed symmetric synaptic contacts with somata, with GABA immunonegative and immunopositive dendritic shafts and with dendritic spines. The results show that GABAergic neurons are heterogeneous with respect to their dendritic and axonal patterns. In addition to the chandelier and basket cells, which have been shown in animal studies to contain GABA, other cell types, most prominently the neurogliaform cells, terminating on the distal parts of neurons, also contain GABA and may have a inhibitory function. Many of the GABAergic terminals make synapses on dendritic spines and shafts in the human cerebral cortex.