Abstract
Astrocytes are vital structures that support and/or protect neighboring neurons from pathology. Although it is generally accepted that glutamate receptors mediate most astrocyte effects, acidβevoked currents have recently attracted attention for their role in this regard. Here, we identified the existence and characteristics of acidβsensing ion channels (ASICs) and the transient receptor potential vanilloid type 1 (TRPV1) in astrocytes. There were two types of currents recorded under the application of acidic solution (pH 6.0) in cultured rat astrocytes. Transient currents were exhibited by 10% of the astrocytes, and sustained currents were exhibited by the other 90%, consistent with the features of ASIC and TRPV1 currents, respectively. Western blotting and immunofluorescence confirmed the expression of ASIC1, ASIC2a, ASIC3, and TRPV1 in cultured and in situ astrocytes. Unlike the ASICs expressed in neurons, which were mainly distributed in the cell membrane/cytoplasm, most of the ASICs in astrocytes were expressed in the nucleus. TRPV1 was more permeable to Na^+^ in cultured astrocytes, which differed from the typical neuronal TRPV1 that was mainly permeable to Ca^2+^. This study demonstrates that there are two kinds of acidβevoked currents in rat astrocytes, which may provide a new understanding about the functions of ligandβgated ion channels in astrocytes. Β© 2010 WileyβLiss, Inc.