TY - JOUR
T1 - Reduced GABAergic inhibition explains cortical hyperexcitability in the wobbler mouse model of ALS
AU - Nieto-Gonzalez, Jose Luis
AU - Moser, Jakob
AU - Lauritzen, Martin
AU - Schmitt-John, Thomas
AU - Jensen, Kimmo
PY - 2011/3/1
Y1 - 2011/3/1
N2 - Amyotrophic lateral sclerosis (ALS) is a progressive degenerative disease of the central nervous system. Symptomatic and presymptomatic ALS patients demonstrate cortical hyperexcitability, which raises the possibility that alterations in inhibitory gamma-aminobutyric acid (GABA)ergic system could underlie this dysfunction. Here, we studied the GABAergic system in cortex using patch-clamp recordings in the wobbler mouse, a model of ALS. In layer 5 pyramidal neurons of motor cortex, the frequency of GABAA receptor-mediated spontaneous inhibitory postsynaptic currents was reduced by 72% in wobbler mice. Also, miniature inhibitory postsynaptic currents recorded under blockade of action potentials were decreased by 64%. Tonic inhibition mediated by extrasynaptic GABAA receptors was reduced by 87%. In agreement, we found a decreased density of parvalbumin- and somatostatin-positive inhibitory interneurons and reduced vesicular GABA transporter immunoreactivity in the neuropil. Finally, we observed an increased input resistance and excitability of wobbler excitatory neurons, which could be explained by lack of GABAA receptor-mediated influences. In conclusion, we demonstrate decreases in GABAergic inhibition, which might explain the cortical hyperexcitability in wobbler mice.
AB - Amyotrophic lateral sclerosis (ALS) is a progressive degenerative disease of the central nervous system. Symptomatic and presymptomatic ALS patients demonstrate cortical hyperexcitability, which raises the possibility that alterations in inhibitory gamma-aminobutyric acid (GABA)ergic system could underlie this dysfunction. Here, we studied the GABAergic system in cortex using patch-clamp recordings in the wobbler mouse, a model of ALS. In layer 5 pyramidal neurons of motor cortex, the frequency of GABAA receptor-mediated spontaneous inhibitory postsynaptic currents was reduced by 72% in wobbler mice. Also, miniature inhibitory postsynaptic currents recorded under blockade of action potentials were decreased by 64%. Tonic inhibition mediated by extrasynaptic GABAA receptors was reduced by 87%. In agreement, we found a decreased density of parvalbumin- and somatostatin-positive inhibitory interneurons and reduced vesicular GABA transporter immunoreactivity in the neuropil. Finally, we observed an increased input resistance and excitability of wobbler excitatory neurons, which could be explained by lack of GABAA receptor-mediated influences. In conclusion, we demonstrate decreases in GABAergic inhibition, which might explain the cortical hyperexcitability in wobbler mice.
U2 - 10.1093/cercor/bhq134
DO - 10.1093/cercor/bhq134
M3 - Journal article
C2 - 20643756
SN - 1047-3211
VL - 21
SP - 625
EP - 635
JO - Cerebral Cortex
JF - Cerebral Cortex
IS - 3
ER -