Heterogeneous expression of connexins in rabbit sinoatrial node cells: correlation between connexin isotype and cell size

Abstract

Rabbit sinoatrial node cells are heterogeneous in terms of connexin expression, and there is a clear cell size-dependence in pattern of connexin expression. Small (putative central) cells express connexin45 but not connexin43, whereas larger (putative peripheral) cells express both connexin45 and connexin43. The co-localization of connexin43 and connexin45 in larger cells raises the possibility that heterotypic or heteromeric connexin43/connexin45 channels could be present in gap junctions at the periphery of the sinoatrial node.