Localization of the tandem pore domain K+ channel TASK-1 in the rat central nervous system

Recently, a new family of potassium channels with two pore domains in tande m and four transmembrane segments has been identified. Seven functional mam malian channels have been reported at this time, These channels give rise t o baseline potassium currents because they are not gated by voltage and exh ibit spontaneous activity at all membrane potentials. Although the physiolo gical role of these ion channels has yet to be determined, three mammalian members of this family (TREK-1, TASK-1, TASK-2) are activated by volatile a nesthetics and may therefore contribute to the central nervous system (CNS) depression produced by volatile anesthetics. In this study we used norther n blot analysis and immunohistochemical localization to determine the expre ssion of TASK-1 subunits in the CNS. TASK-1 immunoreactivity was prominentl y found in astrocytes of the hippocampus, in the median eminence, in the ch oroid plexus, and the granular layer, Purkinje cell layer, and molecular la yer of the cerebellum. In the spinal cord, strong TASK-1 immunoreactivity w as seen in ependymal cells lining the central canal and in white matter. Th ese findings suggest a role for the TASK-1 channel in the production of cer ebrospinal fluid and function of hypothalamic neurosecretory cells. (C) 200 0 Elsevier Science B.V. All rights reserved.