The effect of cell swelling on intracellular calcium concentration ([Ca2+]i) was studied in newborn rat cardiomyocytes. Hypotonic cell swelling induced a fast and transient [Ca2+]i increase (hypotonically induced calcium increase, HICI; 388±47 nM, n=14). HICI was not inhibited by cyclopiazonic acid (CPA), an inhibitor of sarcoplasmic Ca2+-ATPase, nor ryanodine (an inhibitor of calcium-induced calcium release), whereas it was abolished (11±19 nM, n=5) in the absence of external calcium. Thus, HICI appeared to depend exclusively on entry of external calcium. Gadolinium ion (Gd3+), a generic inhibitor of stretch-activated cation channels (SACs), was unable to affect HICI (353±79 nM, n=6). Similarly, HICI was unaffected by internal Na+ depletion and external Na+ omission. These results suggest that neither Gd3+-sensitive SACs nor Na+-Ca2+ exchange is responsible for HICI. Conversely, HICI was inhibited by diltiazem (42±4 nM, n=3) and by membrane predepolarization (40±18 nM, n=5), suggesting an involvement of L-type voltage-activated calciumchannels. Cardiomyocyte swelling was followed by a regulatory volume decrease (RVD). The putative role of HICI in volume regulation was studied by removal of external calcium. This procedure significantly slowed RVD but did not abolish it. In conclusion, newborn rat cardiomyocytes exhibit an external-calcium-dependent HICI which contributes partially to the RVD.
Peripheral blood stem cell transplantation was introduced in 1986 and today is the most common transplantation procedure performed in medicine replacing bone marrow as a source of hematopoietic stem cells. PBSC are able to permanently regenerate a lymphohematopoietic system after myeloablative treatment and are known to facilitate a faster recovery of neutrophils and platelets than bone marrow transplantation..
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.