Caffeine Causes Physical
Changes In Brain Cells
NEW YORK (Reuters Health)- Caffeine may affect the process of long-term memory by changing the structure of dendritic spines, tiny "branches'' found on nerve cells in the central nervous system.
According to Drs. E. Korkotian and Menahem Segal of The Weizmann Institute in Rehovot, Israel, scientists have assumed that changes in the size and shape of these dendritic spines are related to long-term memory, but there has not been any experimental evidence to prove this association. In a new study reported in the Proceedings of the National Academy of Sciences, the Israeli researchers show that when caffeine is added to the cells, the dendrites not only grow longer, but also develop new spines or branches.
Korkotian and Segal studied cells from the hippocampus, a part of the brain that plays an important role in learning and memory. When left alone without stimulation, the cells did not do anything at all over a 3- to 4-hour period. But adding caffeine to the cells raised the level of calcium inside them, causing them to grow about 33% in size. Calcium is an important factor in signal transmission or cellular communication in the brain.
Previous laboratory studies had found that raising the calcium levels in dendritic cells caused them to collapse. Korkotian and Segal suggest that the difference in findings may be that in the previous studies, adding glutamate cause more calcium to enter the cells, while adding caffeine caused the cells to release their stored calcium.
Also, the researchers add, glutamate causes a much larger increase in calcium inside the cells, while caffeine produces a more moderate increase.
These findings suggest that stored calcium "may be even more important than originally proposed'' in the process of increasing calcium in these central nervous system cells, noted the authors.
The investigators also found that new spines tended to grow on parts of the cells that already had lots of spines, rather than in areas where there were not many spines at all.
The findings point to a need for further research into these processes, since they suggest that a modest, temporary rise in calcium levels results in growth and proliferation of these important brain cells, while a larger and more prolonged rise causes the cells to collapse. The implications for long-term memory and learning are not yet clear.