The purpose of this study was to demonstrate the involvement of Ca2+ influx through voltage-independent Ca2+ channels (VICCs) in endothelin-1 (ET-1)-induced transactivation of epidermal growth factor receptor protein tyrosine kinase (EGFR PTK) using the Ca2+ channel blockers LOE-908 and SK&F-96365 in rabbit internal carotid artery vascular smooth muscle cells. ET-1-induced EGFR PTK transactivation was completely inhibited by AG-1478, which is a specific inhibitor of EGFR PTK. In the absence of extracellular Ca2+, the magnitude of EGFR PTK transactivation was near the basal level. Based on sensitivity to nifedipine, which is a specific blocker of voltage-operated Ca2+ channels (VOCCs), VOCCs have minor roles in EGFR PTK transactivation. In contrast, Ca2+ influx through VICCs plays an important role in EGFR PTK transactivation. Moreover, based on the sensitivity of VICCs to SK&F-96365 and LOE-908, VICCs were shown to consist of two types of Ca2+-permeable nonselective cation channels (NSCCs), which are designated NSCC-1 and NSCC-2, and a store-operated Ca2+ channel. In summary, Ca2+influx through VICCs plays an essential role in ET-1-induced EGFR PTK transactivation in rabbit internal carotid artery vascular smooth muscle cells.
Effects of SDF-1α/CXCR4 on vascular smooth muscle cells and bone marrow mesenchymal cells in a rat carotid artery balloon injury model