Neural networks homeostatically regulate their synaptic strengths in response to external changes in activity. This form of homeostatic synaptic scaling occurs in inhibitory networks as well as excitatory networks. Previous studies have shown that a 2-day TTX-induced block of neuronal firing induces a scaling down of miniature postsynaptic inhibitory potentials (mIPSCs) onto cultured visual cortex rat pyramidal cells, accompanied by a decrease in postsynaptic GABAa receptor density (Kilman et al. 2002).

We are currently investigating the complementary scaling up of mIPSCs upon treatment with a GABAa receptor antagonist, and the extent to which anatomical changes at the synaptic level may underlie this phenomenon. To address these questions, we utilize concurrent whole-cell patch clamp recordings and fluorescent microscopy of cultured neuronal networks.
Mechanisms of Inhibitory Synaptic Scaling