Figure 1.

Muscarinic receptors activate I_sADP in organotypic cortical slices. A₁, Under basal conditions, a suprathreshold depolarizing pulse delivered to a layer V cortical pyramidal cell of the prefrontal cortex is followed by a slow afterhyperpolarization. A₂, Administration of carbachol (30 μm) leads to the replacement of this afterhyperpolarization by an sADP that supports sustained spiking. A₃, The current underlying this sADP (I_sADP) can be recorded using a hybrid current–voltage-clamp protocol in which it appears as a slow inward aftercurrent following the spike burst. Inset, I_sADP can also be triggered by depolarizing steps to 0 mV in voltage clamp. B₁, B₂, The carbachol-induced I_sADP is greatly suppressed when intracellular calcium is buffered near rest using BAPTA. B₁ and B₂ depict a paired recording from two pyramidal cells in which B₁ was recorded using control intracellular solution and B₂ using an intracellular solution containing BAPTA to buffer intracellular calcium. C₁, C₂, Reducing extracellular sodium inhibits I_sADP in the control cell depicted in B₁ and B₂.