The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Elevation of intracellular pH (pH i ) enhances the activity of native L-type Ca 2+ channels in cardiac and smooth muscle. We studied the modulation by pH i of expressed L-type Ca 2+ channels comprised of either the α 1C subunits alone or of α 1C plus β 2a subunits. Ca 2+ channels were expressed in human embryonic kidney cells (HEK 293) and pH i was increased from a basal level of 7.3 to 8.3 by exposure of cells to NH 4 Cl (20 mM) or by elevation of extracellular pH to 8.5. Elevation of pH i enhanced the activity of Ca 2+ channels derived by coexpression of α 1C and β 2a subunits. This alkalosis-induced stimulation of channel activity was mainly due to an increase in channel availability. Channels derived by expression of α 1C alone were not affected by intracellular alkalosis. Our results demonstrate that the pH i sensitivity of L-type Ca 2+ channels is conferred by the β subunit of the channel complex.