title: Freshly dissociated mature hippocampal astrocytes exhibit passive membrane conductance and low membrane resistance similarly to syncytial coupled astrocytes.
abstract: Mature astrocytes exhibit a linear current-to-voltage K(+) membrane conductance (passive conductance) and an extremely low membrane resistance (Rm) in situ. The combination of these electrophysiological characteristics establishes a highly negative and stable membrane potential that is essential for basic functions, such as K(+) spatial buffering and neurotransmitter uptake. However, astrocytes are coupled extensively in situ. It remains to be determined whether the observed passive behavior and low Rm are attributable to the intrinsic properties of membrane ion channels or to gap junction coupling in functionally mature astrocytes. In the present study, freshly dissociated hippocampal tissues were used as a new model to examine this basic question in young adult animals. The morphologically intact single astrocytes could be reliably dissociated from animals postnatal day 21 and older. At this animal age, dissociated single astrocytes exhibit passive conductance and resting membrane potential similar to those exhibited by astrocytes in situ. To precisely measure the Rm from single astrocytes, dual-patch single-astrocyte recording was performed. We show that dissociated single astrocytes exhibit a low Rm similarly to syncytial coupled astrocytes. Functionally, the symmetric expression of high-K(+) conductance enabled rapid change in the intracellular K(+) concentrations in response to changing K(+) drive force. Altogether, we demonstrate that freshly dissociated tissue preparation is a highly useful model for study of the functional expression and regulation of ion channels, receptors, and transporters in astrocytes and that passive behavior and low Rm are the intrinsic properties of mature astrocytes.
authors: Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China; and.
authors: Yixing
authors: Y
authors: Du
authors: Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio;
authors: Baofeng
authors: B
authors: Ma
authors: Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio;
authors: Conrad M
authors: CM
authors: Kiyoshi
authors: Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio;
authors: Catherine C
authors: CC
authors: Alford
authors: Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio; Department of Physiology, Institute of Brain Research, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China.
authors: Wei
authors: W
authors: Wang
authors: Department of Neuroscience, Ohio State University Wexner Medical Center, Columbus, Ohio; zhou.787@osu.edu.
authors: Min
authors: M
authors: Zhou
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000502:physiology*; D001703:Biophysics; D004558:Electric Stimulation; D017629:Gap Junctions / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000502:physiology*; D051379:Mice; D018613:Microscopy, Confocal; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D012235:Rhodamines / Q000378:metabolism
chemical_list: D012235:Rhodamines; C050829:sulforhodamine 101; D011188:Potassium
keywords: astrocytes; hippocampus; membrane resistance; passive membrane conductance; patch-clamp recording