The core research theme of the Physiology group of Prof. Dr. L. Leybaert is to elucidate mechanisms and functions of ICWs as a key signaling process in the function of the brain and the cardiovascular system. Plasma mebrane connexins (Cxs) and the channels formed by these proteins importantly contribute to intercellular Ca2+ signaling. Gap junctions (channels directly connecting the cytoplasm of neighboring cells; further abbreviated as GJs) hereby mediate the transfer of IP3 between the cytoplasm of neighboring cells whereas plasma membrane hemichannels (`half of a gap junction channel'; further referred to as HCs) provide a paracrine release pathway for messenger molecules like ATP. Our work is directed at understanding the role of Cx-mediated communication in several pathophysiological processes including blood-brain barrier disruption, cardiac ischemia and arrhythmias, and bystander cell death.