title: High-resolution scanning patch-clamp: new insights into cell function.
abstract: Cell specialization is often governed by the spatial distribution of ion channels and receptors on the cell surface. So far, little is known about functional ion channel localization. This is due to a lack of satisfactory methods for investigating ion channels in an intact cell and simultaneously determining the channels' positions accurately. We have developed a novel high-resolution scanning patch-clamp technique that enables the study of ion channels, not only in small cells, such as sperm, but in submicrometer cellular structures, such as epithelial microvilli, fine neuronal dendrites, and, particularly, T-tubule openings of cardiac myocytes. In cardiac myocytes, as in most excitable cells, action potential propagation depends essentially on the properties of ion channels that are functionally and spatially coupled. We found that the L-type calcium and chloride channels are distributed and colocalized in the region of T-tubule openings, but not in other regions of the myocyte. In addition, chloride channels were found in narrowly defined regions of Z-grooves. This finding suggests a new synergism between these types of channels that may be relevant for action potential propagation along the T-tubule system and excitation-contraction coupling.
authors.affiliation: Division of Medicine, MRC Clinical Sciences Center, Faculty of Medicine, Imperial College of Science, Technology and Medicine, London, UK.
authors.forename: Yuchun
authors.initials: Y
authors.lastname: Gu
authors.forename: Julia
authors.initials: J
authors.lastname: Gorelik
authors.forename: Hilmar A
authors.initials: HA
authors.lastname: Spohr
authors.forename: Andrew
authors.initials: A
authors.lastname: Shevchuk
authors.forename: Max J
authors.initials: MJ
authors.lastname: Lab
authors.forename: Sian E
authors.initials: SE
authors.lastname: Harding
authors.forename: Igor
authors.initials: I
authors.lastname: Vodyanoy
authors.forename: David
authors.initials: D
authors.lastname: Klenerman
authors.forename: Yuri E
authors.initials: YE
authors.lastname: Korchev
mesh_terms: D000818:Animals; D020746:Calcium Channels, L-Type / Q000032:analysis / Q000502:physiology; D018118:Chloride Channels / Q000032:analysis / Q000502:physiology; D006321:Heart / Q000502:physiology*; D007473:Ion Channels / Q000032:analysis* / Q000502:physiology; D009206:Myocardium / Q000737:chemistry* / Q000648:ultrastructure; D018408:Patch-Clamp Techniques / Q000379:methods*; D051381:Rats; D012508:Sarcolemma / Q000737:chemistry* / Q000502:physiology; D012518:Sarcomeres / Q000737:chemistry; D012680:Sensitivity and Specificity
chemical_list: D020746:Calcium Channels, L-Type; D018118:Chloride Channels; D007473:Ion Channels