Characterization of single pacemaker channels in cardiac sino-atrial node cells
- 1 December 1986
- journal article
- Published by Springer Science and Business Media LLC in Nature
- Vol. 324 (6096), 470-473
- https://doi.org/10.1038/324470a0
Abstract
Normal pacemaking in the mammalian heart is driven by spontaneously active cells located in the sino-atrial (SA) node. The rate of firing of these cells and the modulation of this rate by catecholamines are controlled by if, an inward Na- and K-current that turns on at voltages more negative than -40 mV. The 'pacemaker' current if is also present in other types of cell where its ability to produce and modulate a depolarizing process may be useful. For example, in vertebrate photoreceptors if drives the depolarization that terminates the light-induced hyperpolarization. Currents similar to if are also found in hippocampal neurones and DRG neurones. The present report shows for the first time that the opening of single if-channels of low conductance (1 pS) can be resolved using a modification of the patch-clamp technique on isolated SA-node cells. Modulation of if by adrenaline is shown to be mediated by an increase in the probability of channel opening, whereas the single-channel amplitude remains unchanged.Keywords
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