Optical and Electrical Analysis of Suspended Lipid Bilayer Microarrays Formed by Mechanical Liquid Spreading on Horizontal Planar Microelectrode Cavity Arrays

During bursts in KO, the rate was comparable to WT (4.150.3Hz). WT SANs (n=5) showed a 70.556.1% increase in rate after exposure to the b-adrenergic agonist ISO (10mM), while KO showed no increase in average rate. However, when considering only rate during burst activity in KO, 6 out of 10 KO SANs responded significantly to ISO 10mM (52516% increase). The specific If inhibitor ivabradine (IVA, 9mM) reduced the spontaneous pacemaker rate in both WT (n=6) and KO (n=8) SANs (4459% and 58.956.8% decrease, respectively), and even during the bursts in the KO (36517.9% decrease). Thus, NCX1 KO SANs can generate bursts of pacemaker activity similar to WT. These bursts are responsive to both ISO and IVA, consistent with If-mediated pacemaker activity despite the absence of NCX.