beta-amyloid peptide induces the expression of voltage dependent outward rectifying K+ channels in rat microglia

Upregulation of voltage-dependent outward rectifying K+ (Kv) channels has b een reported in activated microglia. Since beta -amyloid peptide (A beta) i s known to activate microglia, we tested whether the exposure of cultured r at microglia to A beta fragment 25-35 (A beta 25-35) induced the Ky current . AP 25-35 in 5-200 nM concentration range significantly increased Ky curre nt density, while there was small change in inward rectifying K+ current de nsity. The full length A beta peptide (A beta 1-42) also increased Ky curre nt. However, the control peptide, A beta 35-25, did not induce Ky current. Most of the Ky current induced by A beta was specifically blocked by the pr esence of antisense deoxyoligonucleotides against Kv1.3, and Kv1.5. Thus, i t is concluded that we have identified Kv1.3 and Kv1.5 as the channel types expressed in A beta -treated microglia. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.