Abstract
The role of calmodulin in exocytotic secretion was studied using digitonin-permeabilized bovine adrenal medullary chromaffin cells. Addition of calmodulin to the permeabilized cells increased Ca 2+-dependent norepinephrine release in a dose-dependent manner. Unlike calmodulin, addition of caldesmon, actin or bovine serum albumin did not increase the release. Calmodulin increased the release at Ca 2+ concentrations of more than 10 −6 M and its effect increased with increase in Mg 2+ concentration. Th release of norepinephrine enhanced by calmodulin was inhibited by tetanus toxin, which specifically inhibits exocytotic secretion. These results indicate directly that calmodulin plays an important role in exocytotic secretion from chromaffin cells.
Sign-in/Register to access full text options 
Free) 
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 call
