Facilitated CA1 hippocampal synaptic plasticity in dystrophin-deficient mice: role for GABAA receptors?
Duchenne muscular dystrophy (DMD) is associated with cognitive deficits that may result from a deficiency in the brain isoform of the cytoskeletal membrane-associated protein, dystrophin. CA1 hippocampal short-term potentiation (STP) of synaptic transmission is increased in dystrophin-deficient mdx mice, which has been attributed to a facilitated activation of NMDA receptors. In this study, extracellular recordings in the hippocampal slice preparation were used first to determine the consequences of this alteration on short-term depression (STD). STD induction was facilitated in mdx as compared with wild-type mice in a control medium. Because brain dystrophin deficiency results in a decreased number of gamma-aminobutyric acid A (GABAA)-receptor clusters, we tested the hypothesis that neuronal disinhibition contributes to the enhanced synaptic plasticity in mdx mice. We found that the GABAA receptor antagonist, bicuculline, increased basal neurotransmission in wild-type, but not in mdx mice and prevented the enhanced STP and STD in the CA1 area of slices from mdx mice. The possibility that altered GABA mechanisms underlie the facilitation of NMDA receptor-dependent synaptic plasticity in mdx mice is discussed.
Vaillend
Cyrille
C
Laboratoire de Neurobiologie de la Mémoire, de l'Apprentissage et de la Communication, CNRS UMR 8620, Orsay, France.
Billard
Jean-Marie
JM
D000818:Animals; D003072:Cognition Disorders / Q000150:complications / Q000503:physiopathology*; D016189:Dystrophin / Q000172:deficiency* / Q000235:genetics; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D006624:Hippocampus / Q000187:drug effects / Q000503:physiopathology*; D036881:Long-Term Synaptic Depression / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D020388:Muscular Dystrophy, Duchenne / Q000150:complications / Q000235:genetics / Q000503:physiopathology*; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D016189:Dystrophin; D011963:Receptors, GABA-A