Figure 4.

Pharmacological depression of basal levels of cAMP enhances coupling. Exposure of slices to the adenylyl cyclase antagonist MDL12330A (10 μm) increases the estimated G_j and the cc, and prevents forskolin-induced modulation (50 μm). Plots in the middle panel are summary graphs of normalized G_j, normalized cc (n = 8 bidirectional connections), and normalized R_input (n = 8 cells; values were 122 ± 15 MΩ in control, 126 ± 19 MΩ in MDL12330A, and 121 ± 18 MΩ in MDL12330A plus forskolin). Plots of the actual values in the different conditions are shown in the bottom panel (Ctrl, control; MDL, MDL12330A; MDL+Frsk, MDL12330A plus forskolin; n = 8 bidirectional connections). Error bars are SEM. The top insets show averaged traces from a recorded pair in the three different conditions. V₁ indicates the voltage responses from the current-injected cell (in millivolts), whereas V₂ indicates the propagated responses expressed as percentage of the steady state of V₁. Responses from the current-injected neuron were normalized to unity to express propagated responses as a percentage of V₁.