, 2008), and here, we have shown that sustained synaptic stimulation for 60 min or more facilitates Kv2 currents, whereas Kv3 currents remain suppressed. The facilitation of Kv2 currents required activity of both PKC and PKG, but not

phosphatases. Multiple sites of Kv2.1 C-terminal phosphorylation cause a proportional shift in the voltage dependence of activation of Kv2.1 (Park et al., 2006), and here, we show that cGMP/PKG signaling also modulates Kv2, perhaps indicative of alternate nitrergic phosphorylation sites, which will be explored in future studies. This new mechanism for physiological regulation of K+ channel activity HDAC inhibition is important for our understanding of brain physiology. It shows that spontaneous

and moderate synaptic excitation influences target neuron excitability and will complement synapse-specific forms of modulation. The result is important for integrating knowledge of single neurons and network behavior in vitro and after isolation from sensory input because our results show that ion channel activity can undergo substantial changes over periods of minutes to hours. Brain BVD-523 order slices were prepared from P12 to P16 CBA/Ca mice, which were killed by decapitation in accordance with the Animals, Scientific Procedures Act, 1986. Transverse slices containing MNTB (200 μm) were cut in low-sodium artificial CSF (Supplemental Experimental Procedures) at ∼0°C. To identify neurons with intact calyceal synaptic connections, a calcium-imaging

technique was used. Horizontal hippocampal slices of 250 μm thickness were prepared as described previously (Brown and Randall, 2005) (Supplemental Experimental Procedures). Hippocampal EPSCs were insensitive to DCG-IV (Figure S1C) (Lawrence et al., 2004), suggesting predominantly commissural inputs. Whole-cell recordings were made from identified neurons, visualized with 60× objectives on a Nikon FS600 microscope fitted with differential interference contrast (DIC) optics using a MultiClamp 700B amplifier and pClamp 9.2 software (Molecular Devices), sampling at 50 kHz, and filtering at 10 kHz. Patch pipettes were pulled from filamented borosilicate glass (GC150F-7.5; Harvard Apparatus, Edenbridge, UK) with a 2-stage vertical puller (PC-10; Narishige, Tokyo, Japan). Pipettes (2.5–3.5 MΩ) were filled with a solution containing: KCl 110 mM, HEPES heptaminol 40 mM, EGTA 0.2 mM, MgCl2 1 mM, CaCl2 0.1 mM, Na2phosphocreatine 5 mM, and L-arginine 1 mM; pH was adjusted to 7.2 with KOH. Current-voltage (I/V) relationships were measured before and after synaptic conditioning (PC) in separate populations of neurons to avoid neuronal dialysis during the 1 hr conditioning period. Final whole-cell access resistance was <7 MΩ, and series resistance was routinely compensated by 70% (10 μs lag). Displayed raw traces are not corrected for leak or capacitive currents but are low-pass Bessel filtered (2 kHz).