Figure 7.

Extracellular d-Ser increase in response to NBM stimulation is absent in IP₃R2-KO mice. A, Extracellular d-Ser concentration peaks in the first 10 min after NBM stimulation (red bar) in WT mice (blue circle), in contrast to IP₃R2-KO mice (green square) (**p < 0.01). B, Supplementation of d-Ser to IP₃R2-KO mice during the costimulation of whiskers and NBM rescues LTP induction. Inset, Averaged evoked response in control period (green) and 60 min after costimulation (light green) from a representative animal. Scale bar: 200 μV, 20 ms. C, Bar graph comparing air puff-triggered LFP enhancement in IP₃R2-KO mice at 60 min with air puff only, costimulation, or costimulation plus d-Ser supplementation, respectively (**p < 0.01). D, Proposed involvement of astrocytes in NBM-gated potentiation of synaptic transmission in the cortex.