Dysbindin-1 loss compromises NMDAR-dependent synaptic plasticity and contextual fear conditioning

Area of Science:

• Neuroscience
• Genetics
• Psychiatry

Background:

• Genetic variants in DTNBP1, encoding dysbindin-1, are linked to schizophrenia and cognitive deficits.
• Hippocampal dysfunction is implicated in memory impairments observed in schizophrenia.
• NMDAR-dependent synaptic plasticity in the hippocampus is crucial for memory.

Purpose of the Study:

• To investigate the impact of reduced dysbindin-1 expression on NMDAR-dependent synaptic plasticity.
• To determine if dysbindin-1 deficiency affects hippocampal-dependent memory, specifically contextual fear conditioning.

Main Methods:

• Electrophysiological recordings in acute hippocampal slices from mice with varying Dtnbp1 gene dosages (0, 1, or 2 null mutant alleles).
• Measurement of field excitatory postsynaptic potentials (fEPSPs) in the CA1 region following Schaffer collateral stimulation.
• Behavioral assessment of contextual fear conditioning in adult mice.

Main Results:

• Mice homozygous for the Dtnbp1 null mutation showed significantly reduced NMDAR-dependent synaptic potentiation in the hippocampus.
• This impairment in synaptic plasticity was partially rescued by glycine, an NMDAR coagonist.
• Homozygous null mice exhibited deficits in contextual fear conditioning, indicating impaired learning and memory.

Conclusions:

• Loss of dysbindin-1 function impairs hippocampal synaptic plasticity.
• Dysbindin-1 deficiency contributes to hippocampal memory deficits.
• These findings suggest a potential mechanism linking dysbindin-1 to cognitive impairments in schizophrenia.