Ischaemia-induced long-term hyperexcitability in rat neocortex.

The long-term structural and functional consequences of transient forebrain ischaemia were studied with morphological, immunohistochemical and in vitro electrophysiological techniques in the primary somatosensory cortex of Wistar rats. After survival times of 10-17 months postischaemia, neocortical slices obtained from ischaemic animals were characterized by a pronounced neuronal hyperexcitability in comparison with untreated age-matched controls. Extra- and intracellular recordings in supragranular layers revealed all-or-none long-latency recurrent responses to orthodromic synaptic stimulation of the afferent pathway.

Astrocytic GABA receptors.

GABA receptors are distributed widely throughout the central nervous system on a variety of cell types. It has become increasingly clear that astrocytes, both in cell culture and tissue slices, express abundant GABAA receptors. In astrocytes, GABA activates Cl(-)-specific channels that are modulated by barbiturates and benzodiazepines; however, the neuronal inverse agonist methyl-4-ethyl-6, 7-dimethoxy-beta-carboline-3-carboxylate enhances the current in a subpopulation of astrocytes.

Postsynaptic potentials mediated by GABA and dopamine evoked in stellate glial cells of the pituitary pars intermedia.

Studies have shown that many glial cells in the CNS possess receptors for neurotransmitters and that synapse-like contacts exist between glial cells and axonal terminals. Although synapse-like contacts are present between the glial cells (stellate cells) of the pituitary pars intermedia and the axons from the arcuate nucleus, it is not known whether these cells are under synaptic control. The objective of the present study was to determine whether transmitter-mediated postsynaptic potentials occurred in the stellate cells of the rat pituitary pars intermedia.