Fig. 2.

Developmental decline in the ω-CgTx sensitivity of GABAergic IPSCs in the LD thalamic nucleus. IPSCs were recorded in the presence of CNQX (10 μm), d-AP-5 (50 μm), and strychnine (0.5 μm) and could be blocked by bicuculline (10 μm; data not shown).A, At P10, ω-CgTx (3 μm) reduced the amplitude of IPSCs by 53%. Subsequent application of ω-Aga-IVA (200 nm) blocked the remaining IPSCs. Sample records of 10 IPSCs before ω-CgTx application (1), after ω-CgTx application (2), and after ω-Aga-IVA application (3) were averaged and superimposed (A, B). The holding potential was −70 mV. B, At P19, ω-CgTx no longer affected IPSCs, whereas ω-Aga-IVA almost completely blocked IPSCs. C, The fraction of IPSCs blocked by ω-CgTx application at different postnatal ages. Symbols and error bars as above (n = 5–6).