Calcium transport by subcellular fractions of rat, dog and monkey brains

Abstract

1. 1. The abilities of mitochondria and microsomes from the rat brain and from different areas of the dog and monkey brains to bind calcium were determined under identical conditions. In contrast to other excitable tissues, such as heart and skeletal muscle, the rat brain mitochondria bound more calcium than the microsomes. 2. 2. Mitochondria obtained from the cerebral cortex, cerebellum, medulla, pons and spinal cord of the dog brain were also observed to bind more calcium than the microsomes. On the other hand, the calcium-binding ability of the dog hypothalamus mitochondria was lower than microsomes whereas the values for calcium binding by subcellular fractions of the dog thalamus and hippocampus were not different from each other. 3. 3. The mitochondria obtained from the monkey cerebral cortex, cerebellum, pons, hypothalamus, thalamus and hippocampus were found to bind less calcium in comparison to the microsomes. However, no significant difference was noted between the calcium-binding abilities of the mitochondria and microsomes of the monkey medulla and spinal cord. 4. 4. The results suggest that the predominant role of either mitochondria or microsomes in regulating the intracellular calcium is tissue and species dependent.