Overexpression of PIP₂ depleting-sequestering constructs in SCG neurons decreases I_Ca density and reduces muscarinic suppression. A-C, PTX-treated SCG neurons were studied in perforated-patch configuration. Voltage protocols and other experimental conditions and labeling are as in Figure 2. Cells were transfected using the biolistic particle delivery system (gene gun; see Materials and Methods for details) with Akt-PH (A), Lyn-PH-PP (B), or PLCδ-PH (C). Color insets on the right show images of the transfected neurons. Cd²⁺, CdCl₂. D, Pooled time courses of muscarinic suppression of I_Ca in Akt-PH-(white circles; n = 8) and PLCδ-PH-transfected (black circles; n = 8) cells, temporally aligned to the time of oxo application. Data were fitted by the equation y = y₀ + a/(1 + exp(-(t_1/2 - t)/k)), where y is I/I_o, a is y_max - y_min, t_1/2 is a half-time of inhibition, and k is a slope factor. For Akt-PH-expressing cells, y₀, a, t_1/2, and k were 0.01, 1.1, 60.4, and -26.3, respectively; for PLCδ-PH-expressing cells, they were 0.02, 1.1, 62.2, and -25.6, respectively. E, Bars on the left summarize data of the current density of the Akt-PH-, Lyn-PH-PP-, and PLCδ-PH-expressing neurons (n = 18, 23, and 18, respectively), and those on the right summarize their muscarinic modulation (n = 10, 12, and 10, respectively). Significance: ^*p ≤ 0.05; ^**p ≤ 0.01; ^***p ≤ 0.001.