Figure 3.

GABA-mediated inhibition involves tyrosine phosphorylation. (A) Time course of Ca²⁺ current inhibition by 100 μM GABA (applied for time indicated by horizontal bar) in control cells (○) or in cells bathed in 250 μM sodium pervanadate (•). (B) Autoradiogram of ³²P-labeled proteins from sensory neurons. Cells were labeled metabolically with ³²P_i, treated with 100 μM GABA, solubilized, and immunoprecipitated with 4G10 as described in Materials and Methods. GABA applied for times indicated below each lane. (C) Time course for inhibition of N current during prolonged exposure to 100 μM GABA (horizontal bar). Solid line is least-squares fit to single-exponential function (τ = 14 s).