We also examined the effects of selective HDACis on the expression level of KCa3.1 in the CD4+CD25− T cells of IBD model mice: AATB, the half maximal inhibitory concentration (IC50) = 0.007 and 0.049 μM for HDAC1 and HDAC2, respectively and T247, IC50 = 0.24 μM for HDAC3 [31,32]. The gene discussed is KCNN4; the disease is inflammatory bowel disease.