Our finding that NMDAR-LTD is independent of transcription differs from a previous report (Kauderer and Kandel, 2000) for reasons that are unclear. Of course, we cannot

discount a role of transcription at times beyond the 3 hr that we have investigated here. CHIR-99021 research buy Indeed, a plausible role for the increase in nuclear STAT3 activity that we have observed may be in the regulation of proteins that are required for later phases of the NMDAR-LTD process. Our findings strongly suggest that STAT3 has nonnuclear actions that are required for NMDAR-LTD. Unfortunately, little is known concerning the role of STATs on targets other than DNA. Recent evidence has implicated the regulation of microtubules in NMDAR-LTD (Kapitein et al., 2011). Interestingly, it has been shown that STAT3 can directly interact with proteins associated with microtubules, such as stathmin and SCG10-like protein (SCLIP), and regulate their polymerization (Gao and Bromberg, 2006, Ng et al., 2006 and Ng et al., 2010). One possibility then is that STAT3 could regulate the stabilization of microtubules, a mechanism that is believed to be rapid, dynamic and reversible (Gao and Bromberg, 2006). The role of JAKs in oncogenesis

and pathologies of the immune system make these kinases attractive potential therapeutic targets. In particular, JAK2 mutations underlie the myeloproliferative Alectinib solubility dmso disorders: polycythemia vera, essential thrombocytosis, and primary

myelofibrosis (Delhommeau et al., 2010). Since JAK2 is overactivated in these pathologies, a specific JAK inhibitor has potential utility in the treatment of these diseases and several clinical trials for JAK2 inhibitors are underway (Quintás-Cardama et al., 2011). However, the effect of available JAK2 inhibitors on the other JAK isoforms and the inhibition of the central role JAKs play Thiamine-diphosphate kinase as downstream effectors of cytokine receptors have been major issues so far (Pesu et al., 2008 and Wilks, 2008). The JAK2 inhibitor AG490 has also been shown to affect spatial learning and memory (Chiba et al., 2009b). It was suggested that this impairment was due to the downregulation of the enzyme choline acetyltransferase and to the desensitization of the M1-type muscarinic acetylcholine receptor (Chiba et al., 2009b). We now show that inhibiting JAK2 results in blockade of a specific form of synaptic plasticity, NMDAR-LTD. A complete description of experimental procedures is available online in the supplemental information. A complete list of the inhibitors used is available in the supplemental information. Organotypic slices were transfected using biolistic transfection with HuSH shRNA constructs in pGFP-V-RS vector (Origene Technologies, Rockville, MD, USA).