Abstract
Recent studies using confocal microscopy combined with patch clamping on single sinoatrial (SA) node pacemaker cells suggest that Ca 2 + release from the sarcoplasmic reticulum (SR) during diastole may play a prominent role in the late phase of pacemaker depolarization. The present study was designed to test this hypothesis in the intact SA node. We investigated the effects of a high concentration of ryanodine, which is known to disable SR Ca 2 + release, on spontaneous activity of isolated rabbit right atrium including the whole SA node by using an extracellular potential mapping technique. Inhibition of SR Ca 2 + release by 30 μM ryanodine caused only a moderate reduction of the spontaneous firing rate (by 20.0′2.8 %, n=4) of the intact SA node. This observation is inconsistent with previous data obtained from single pacemaker cells. Physiological significance of SR Ca 2 + release in the regulation of SA node pacemaker activity is still unsettled.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
