Browsing by Subject "subcellular fractionation"

Kainate receptors (KARs) are glutamate receptors that modulate neurotransmission and neuronal excitability. They assemble from five subunits (GRIK1-5 or GluK1-5) present at both pre- and postsynaptic membranes. KAR function is regulated by neuropilin and tolloid-like (NETO) proteins, which also regulate postsynaptic GRIK2 abundance. Some KAR subunit gene variants associate with psychiatric disorders. Moreover, Grik1, Grik2 and Grik4 knock-out (KO) mice display changes in anxiety- and fear-related behaviours. In previous work, Neto2 KO mice expressed higher fear and impaired fear extinction in the fear conditioning paradigm. We hypothesised that this phenotype could be due to reduced KAR subunit abundance in fear-related brain regions, i.e. ventral hippocampus, amygdala and medial prefrontal cortex (mPFC). We specifically investigated GRIK2/3 and GRIK5 levels in the subcellular synaptosomal (SYN) fraction using western blot. We did not observe any difference between genotypes in any of the brain regions. However, our statistical power may have been insufficient, particularly for amygdala and mPFC. Also, an effect on synaptic KAR subunit abundance might be specific to either pre- or postsynaptic compartment, and thus more difficult to detect in SYN fractions. Alternatively, NETO2 absence may affect KAR actions instead of their subunit levels in fear-related brain regions, which could be examined through electrophysiological recordings. Ultimately, unravelling how a molecular system without NETO2 gives rise to fear behaviour in mice may lead to a better understanding of fear-related disorders in human and to new therapeutic strategies.