Fig. 7.

Morphological and electrophysiological characteristics of cells isolated from PCC. a Typical aspect of a spontaneously beating PCC. Origin of isolated cells characterized by patch-clamp recordings are framed for illustration. Scale bar = 50 μm. b Single cells isolated from PCC center, immunostained with anti-HCN4 (green) and counterstained with propidium iodide (red) showed typical elongated cell morphology and intense membrane expression of HCN4. Signals were visualized by confocal microscopy. Scale bars = 50 μm. c–e Spontaneous action potentials (APs) (n = 41) were recorded from individual cells dissociated from PCC using the whole-cell voltage-clamp technique. Representative recordings are depicted and show AP morphologies resembling (c) central sinoatrial node (SAN) (n = 21), (d) atrial (n = 15), and (e) peripheral SAN (n = 5) cells