Abstract
Isolated dog cardiac microsomes (CSR) showed Ca2+ uptake by adding ATP, which was measured with the optical density change of Arsenazo III (Ca2+-sensitive dye) using Hitachi dual wave length spectro photometer at 30°C. Maximal Ca2+-uptake (18.5±1.4nmol/mg) was attained at 1min after adding 0.1mM ATP to 1 mg/ml of CSR in the presence of 50μM Arsenazo III. This Ca2+-uptake was inhibited by 0.5mM Nicomol (about 39%) and Nicotinic Acid Amid (about 28%) but not by Nicotinic Acid. It was suggested that the Nicomol and Nicotinic Acid Amid possibly delay the cardiac muscle contraction and relaxation.
