Abstract
Calcium activated chloride (ClCa) channels are an important contractile mechanism in smooth muscle cells. Activation of these channels by calcium (Ca2+) ions leads to Cl- efflux and membrane depolarization. This depolarization then favors the activation of voltage-gated Ca2+ channels (e.g. L-type), providing a positive feed-back loop that allows for sustained contraction.The molecular candidate encoding for this channel has remained elusive, although a number of suggestions have been investigated. The latest contender to emerge is TMEM16A (Anoctamin). Evidence so far confirms that over-expression of TMEM16A generates Cl- currents with the same time-dependent kinetics and Ca2+ sensitivity as recorded through ClCa channels in smooth muscle cells.This study investigated expression profiles of TMEM16A in a number of vascular tissues across a number of species. The aim of this study was to confirm the role of TMEM16A as a potential candidate encoding for ClCa currents (IClCa) in native vascular myocytes.Smooth muscle cells were enzymatically isolated from the mouse portal vein (PV), aorta and carotid artery (CA), rat pulmonary artery (PA), and the rabbit PA. Robust IClCa, exhibiting distinctive voltage-dependent kinetics, were recorded from all of the tissue preparations mentioned.RT-PCR was performed, using species-specific primers designed against the available sequences for TMEM16A. Mouse aorta, PA, CA and PV, rat aorta, PA and PV, and rabbit PA tissues were studies. All samples showed clear expression of TMEM16A.Immunocytochemistry revealed specific expression of TMEM16A in rat PA, and mouse PV, CA and aorta isolated myocytes. This was apparent throughout the cytoplasm, with punctuate “hotspots”. Western blot analysis showed bands of the expected molecular weight in mouse aorta, PV and CA.In summary, we have demonstrated that TMEM16A is a viable candidate for the encoding of ClCa channels in vascular smooth muscle.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
