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Alterations in the γ‐Aminobutyric Acid‐Gated Chloride Channel Following Transient Forebrain Ischemia in the Gerbil
Author(s) -
Mileson Beth E.,
Ehrmann Martha L.,
Schwartz Rochelle D.
Publication year - 1992
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1992.tb09761.x
Subject(s) - muscimol , gerbil , hippocampus , medicine , striatum , endocrinology , chemistry , neuroscience , hippocampal formation , entorhinal cortex , forebrain , ischemia , gabaa receptor , biology , receptor , central nervous system , dopamine
The role of inhibitory neurotransmission in selective neuronal degeneration after transient forebrain ischemia was studied by binding of t ‐[ 35 S]butylbicyclophosphorothionate ([ 35 S]TBPS) to the γ‐aminobutyric acid (GABA)‐gated chloride channel and measurement of GABA A receptor function in Mongolian gerbil brain. [ 35 S]TBPS binding to the hippocampus, striatum, and cortex quantified by autoradiography and muscimol‐stimulated 36 Cl ‐ uptake in synaptoneurosomes of the same regions were examined 1, 4, and 29 days after a 5‐min bilateral carotid occlusion. [ 35 S]TBPS binding was decreased in the pyramidal cell dendritic layers, stratum oriens, and stratum lacunosum‐moleculare of the CA1 hippocampus, 4 and 29 days after occlusion, and in the stratum radiatum 29 days after occlusion. [ 35 S]TBPS binding sites in the lateral striatum decreased 47% 4 days after occlusion. At the same time, there was a corresponding decrease in muscimol‐stimulated 36 CI ‐ uptake in the striatal synaptoneurosomes. Muscimol‐stimulated 36 Cl ‐ uptake in the hippocampus decreased slightly 4 days after occlusion and more so after 29 days, although these decreases were not significant. No changes were observed in somatosensory cortex at any time point. These data suggest that a portion of GABA A receptors in areas sensitive to ischemic insult are associated with degenerating neurons, whereas other GABA A receptors are spared.