Expression of Kv1.5 K+ channels in activated microglia in vivo

✍ Scribed by Ilo Jou; Hankyoung Pyo; Sungkwon Chung; So Young Jung; Byoung Joo Gwag; Eun-Hye Joe

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 204 KB
• Volume: 24
• Category: Article
• ISSN: 0894-1491
• DOI: 10.1002/(sici)1098-1136(199812)24:4<408::aid-glia6>3.0.co;2-d

✦ Synopsis

We examined the expression of outward rectifier K ϩ channels in activated microglia in vivo. For this purpose, lipopolysaccharide (LPS, 2 µg) was injected into the cortex near the hippocampal region of rat brains, and K ϩ channel expression was examined using antibodies against shaker-type K ϩ channels, Kv1.5 and Kv1.3. OX-42positive microglia were found around the injection sites from 8 h after the LPS injection and remained there for 3 days. The OX-42-positive microglia expressed Kv1.5 immunoreactivity, and the time course of Kv1.5 expression was closely correlated with that of OX-42. In saline-injected brains, OX-42-positive cells also expressed Kv1.5 immunoreactivity even though far fewer OX-42-positive cells were found. Increase of Kv1.5 expression after LPS injection was also demonstrated by immunoblot analysis. On the other hand, Kv1.3 immunoreactivity was barely detected in OX-42-positive cells over the entire experimental period. The expression of Kv1.5 preceded that of inducible nitric oxide synthase (iNOS), which is a prominent indication of microglial activation. iNOS was not detectable until 12 h, and thereafter it was maintained for 3 days together with Kv1.5 and OX-42. These results suggest that in vivo as well as in vitro activated microglia expressed outward K ϩ channels and that some of the channels at least are Kv1.5.