AMPA receptors (AMPARs) mediate fast excitatory synaptic currents in the superficial dorsal horn (SDH) of the spinal cord. Pain-processing neurons in lamina II of the SDH receive excitatory input from peripheral fibres (mainly C-fibres) as well as local input from excitatory interneurons. Transmembrane AMPAR regulatory proteins (TARPs) such as γ-2 (stargazin) are critical in determining the trafficking and gating of AMPARs in many brain regions (1), but their role in the spinal cord is less clear. TARPs have been implicated in pain (2), yet there is no direct evidence to demonstrate that TARPs regulate AMPAR-mediated currents in the SDH. Furthermore, there is little information about the distribution of TARP subtypes at specific lamina II inputs.To gain insight into TARP modulation of AMPARs in the SDH, we made whole-cell patch-clamp recordings from neurons in lamina II of acute spinal slices from stargazer (stg/stg) mice that lack the prototypical TARP γ-2. CNQX, a partial agonist at AMPARs associated with Type-I TARPs (γ-2, -3, -4, -8) (3,4), induced whole-cell currents in wild-type cells (9/12 cells; -39.4±8.2 pA) but not in stg/stg cells (0/8), suggesting that γ-2 may be the only Type-I TARP present. The amplitude of focally evoked quantal events, recorded in the presence of extracellular strontium, was also reduced in stg/stg (-13.8±0.7 pA, n=9) compared with wild-type controls (-21.9±1.7 pA, n=8). To promote the selective release of glutamate from TRPV1 expressing C-fibres, we applied the TRPV1 agonist capsaicin (5). Capsaicin increased the frequency of miniature EPSCs (mEPSCs) in approximately half of the lamina II cells examined (5.60 ± 2.83-fold in 13 cells; no response in 15 cells). Unexpectedly, the mean amplitude of capsaicin evoked mEPSCs was similar between wild-type (-21.9±1.5 pA, n=13) and stg/stg cells (-23.5±2.6pA, n=9), suggesting that γ-2 is not associated with AMPARs at TRPV1-expressing C-fibre synapses. In contrast, the amplitude of mEPSCs recorded in control conditions, prior to the addition of capsaicin in this subset of cells, was reduced in stg/stg compared to wild-type (-15.7±0.7 versus -21.5±1.7 pA, n=9 and 8) suggesting γ-2 is normally present at other synapses. Interestingly, the amplitude of baseline mEPSCs in cells that were insensitive to capsaicin did not differ (-19.1±2.2 pA and -17.5±1.0 pA, n=11 and 15).Collectively, these data suggest that γ-2 is the major Type-I TARP of lamina II neurons and that it is important in regulating the excitatory drive between lamina II interneurons. However, it appears to play a lesser role at synapses receiving input from TRPV1-expressing C-fibres.