Tumor Necrosis Factor Alpha Mediates GABA_A Receptor Trafficking to the Plasma Membrane of Spinal Cord Neurons In Vivo

Figure 5

Increased GABA_ARs on the plasma membrane of spinal neurons after TNFα injection. ((a) and (b)) An image analysis program identified the confocal plane with the greatest colocalization of GABA_AR and synaptophysin for each motor neuron. ((c) and (d)) A 2 μm wide cutout of the image containing the somatic plasma membrane. ((e) and (f)) Boxed plasma membrane fractions enlarged to demonstrate representative differences in extrasynaptic (green) and synaptic (yellow) GABA_AR puncta on the plasma membrane following the highest and lowest injections of TNFα  in vivo. ((g) and (h)) The highest dose of TNFα yielded a significant increase in extrasynaptic and synaptic GABA_ARs on the plasma membrane (extrasynaptic GABA_AR *𝑃<0.001 from low and middle dose; synaptic GABA_AR *𝑃<0.001 from low and middle dose). Furthermore, the lowest dose of TNFα produced a significant increase in extrasynaptic GABA_ARs relative to the middle dose (^†𝑃=0.002). Bars represent group means across > 800 confocal image stacks (12 subjects, 𝑛=4 subjects per group). Error bars reflect SEM. Scale bar, 30 μm.