Fluorescence recovery after photobleaching experiments of SEP-GABA_AR γ2 at excitatory and inhibitory synapses.

(A) Dendritic portion of a neuron co-transfected with SEP-GABA_ARγ2 (green) and DsRed-homer1c (red) constructs. Scale, 1 µm. Note that SEP-GABA_AR γ2 (green) form clusters that are not colocalized with DsRed-homer1c (red) fluorescent clusters. (B) Normalized SEP-GABA_ARγ2 FRAP fluorescence recovery curves at inhibitory synapses (green, inh), excitatory synapses (red, exc), and in extrasynaptic compartment (black, ex). (C) Percentage (mean ± SEM) of SEP-γ2 fluorescence recovery at inhibitory synapses (inh, green), excitatory synapses (exc, red) and extrasynaptically (ex, black). Note the increase in the size of the pool of slowly mobile γ2 at excitatory synapses as compared with the extrasynaptic compartment (t-test, ***p<10⁻³). (D–E) Time constants (mean ± SEM) for the fast (D) and slow (E) pool, obtained from the double exponential fit (see Materials and Methods) applied to the data in B for inhibitory (green, inh), excitatory (red, exc) synapses or extrasynaptic area (black, ex) (t test, ns: not significant, *: p<0.05, **: p<0.01; ***: p<0.001).