Stimulation of heart sarcolemmal Na+-Ca2+ exchange by concanavalin A

The effects of Concanavalin A (Con A) on membrane Ca2+ translocation activities were examined by employing rat heart sarcolemmal preparations. Con A stimulated Na+-dependent Ca2+ uptake and ATP-dependent Ca2+ uptake activities in the sarcolemmal vesicles; maximal stimulation was seen at a concentration of 10 microgram/ml. These effects of Con A were blocked by alpha-metylmannoside. Sarcolemmal Na+-induced Ca2+ release was not affected by Con A. It is suggested that Con A-like substances may play a regulatory role in Ca2+-translocation processes of heart sarcolemma.