Intercellular calcium waves in primary cultured rat mesenteric smooth muscle cells are mediated by connexin43

Intercellular Ca²⁺ wave propagation between vascular smooth muscle cells (SMCs) is associated with the propagation of contraction along the vessel. Here, we characterize the involvement of gap junctions (GJs) in Ca ²⁺ wave propagation between SMCs at the cellular level. Gap junctional communication was assessed by the propagation of intercellular Ca²⁺ waves and the transfer of Lucifer Yellow in A7r5 cells, primary rat mesenteric SMCs (pSMCs), and 6B5N cells, a clone of A7r5 cells expressing higher connexin43 (Cx43) to Cx40 ratio. Mechanical stimulation induced an intracellular Ca²⁺ wave in pSMC and 6B5N cells that propagated to neighboring cells, whereas Ca²⁺ waves in A7r5 cells failed to progress to neighboring cells. We demonstrate that Cx43 forms the functional GJs that are involved in mediating intercellular Ca²⁺ waves and that co-expression of Cx40 with Cx43, depending on their expression ratio, may interfere with Cx43 GJ formation, thus altering junctional communication.