Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

1. The electrical activity of sinoatrial node cells is heterogeneous. To understand the reasons for this, the density of the delayed-rectifier K + current and its two components, i K,r and i K,s , as a function of the size (as measured by cell capacitance) of rabbit sinoatrial node cells was investigated using the whole-cell voltage-clamp technique at 35°C. 2. i K,r and i K,s were isolated using E-4031 and 293B. Features of the E-4031-sensitive and 293B-insensitive currents corresponded well to those of i K,r , while features of the E-4031-insensitive and 293B-sensitive currents corresponded well to those of i K,s . 3. The densities of the outward current under control conditions and the drug-sensitive and -insensitive currents were significantly (P < 0.01) correlated with cell capacitance, with current densities being greater in larger cells. 4. The effects of partial blockade of i K,r by 0.1 μM E-4031 on spontaneous action potentials were greater in smaller cells. 5. It is concluded that there are cell size-dependent differences in the density of the i K,r and i K,s components, and these may be involved in the heterogeneity of the electrical activity of single sinoatrial node cells as well as that of the intact sinoatrial node.

Original publication

DOI

10.1111/j.1469-7793.2001.t01-1-00703.x

Type

Journal article

Journal

Journal of Physiology

Publication Date

15/09/2001

Volume

535

Pages

703 - 714