title: Patch-clamp electrophysiology of intracellular Ca2+ channels.
abstract: The modulation of cytoplasmic free Ca(2+) concentration ([Ca(2+)]i) is a universal intracellular signaling pathway that regulates numerous cellular physiological processes. Ubiquitous intracellular Ca(2+)-release channels localized to the endoplasmic/sarcoplasmic reticulum-inositol 1,4,5-trisphosphate receptor (InsP3R) and ryanodine receptor (RyR) channels-play a central role in [Ca(2+)]i signaling in all animal cells. Despite their intracellular localization, electrophysiological studies of the single-channel permeation and gating properties of these Ca(2+)-release channels using the powerful patch-clamp approach have been possible by application of this technique to isolated nuclei because the channels are present in membranes of the nuclear envelope. Here we provide a concise description of how nuclear patch-clamp experiments have been used to study single-channel properties of different InsP3R channels in the outer nuclear membrane. We compare this with other methods for studying intracellular Ca(2+) release. We also briefly describe application of the technique to InsP3R channels in the inner nuclear membrane and to channels in the outer nuclear membrane of HEK293 cells expressing recombinant RyR.
authors.affiliation: Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Don-On Daniel
authors.initials: DO
authors.lastname: Mak
authors.forename: Horia
authors.initials: H
authors.lastname: Vais
authors.forename: King-Ho
authors.initials: KH
authors.lastname: Cheung
authors.forename: J Kevin
authors.initials: JK
authors.lastname: Foskett
mesh_terms: D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D002413:Cations, Divalent / Q000378:metabolism; D002460:Cell Line; D003584:Cytological Techniques / Q000379:methods*; D006801:Humans; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism*; D009685:Nuclear Envelope / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods*
chemical_list: D015220:Calcium Channels; D002413:Cations, Divalent; D053496:Inositol 1,4,5-Trisphosphate Receptors; D002118:Calcium