Summary
Astrocytes are ubiquitous in the brain and are widely held to be largely identical. However, this view has not been fully tested and the possibility that astrocytes are neural circuit-specialized remains largely unexplored. Here, we used multiple, integrated approaches including RNA-Seq, mass spectrometry, electrophysiology, immunohistochemistry, serial block-face scanning electron microscopy, morphological reconstructions, pharmacogenetics, as well as diffusible dye, calcium and glutamate imaging, to directly compare adult striatal and hippocampal astrocytes under identical conditions. We found significant differences between striatal and hippocampal astrocytes in electrophysiological properties, Ca2+ signaling, morphology and astrocyte-synapse proximity. Unbiased evaluation of actively translated RNA and proteomic data confirmed significant astrocyte diversity between hippocampal and striatal circuits. We thus report core astrocyte properties, reveal evidence for specialized astrocytes within neural circuits and provide new, integrated database resources and approaches to explore astrocyte diversity and function throughout the adult brain.