New research from the University of Edinburgh in Scotland and published in the Journal of Neuroscience reveals how two receptors in older brains react to the stress hormone cortisol, already known for its link to another unpleasant consequence—the accumulation of stubborn belly fat. Cortisol was already connected to increasing forgetfulness as we age; this research investigated the mechanism of how it is involved.
The study found that one receptor was activated by low levels of cortisol, which helped memory. But when cortisol levels were too high they spilled over onto a second receptor that activated brain processes that led to memory impairment. While the researchers found that high levels of the stress hormone in aged mice made them less able to remember how to navigate a maze, the problem was reversed when the receptor linked to poor memory was blocked. The study helps us understand why too much stress over a prolonged period of time interferes with the normal processes in storing everyday memories.
Said Dr. Joyce Yau of the University's Centre of Cardiovascular Science, “We now know that lowering the levels of these stress hormones will prevent them from activating a receptor in the brain that is bad for memory. Understanding the mechanisms in the brain, which affect memory as we age, will help us to find ways to combat conditions linked to memory loss.”
The study was funded by the Medical Research Council. “This research highlights some interesting, original concepts relating to why memory loss occurs in old age. With people living ever longer, the MRC is really focusing on research which allows elderly people not just to survive, but also to stay healthy,” said Professor Chris Kennard, Chairman of the MRC's Neuroscience and Mental Health Board.
The researchers are now investigating a new chemical compound that blocks an enzyme involved in producing stress hormones within cells. This could possibly lead to the development of a drug to slow the normal decline in memory associated with aging or even improve memory in the already very old.
Editor’s note: If you’re experiencing stress from daily living or from caregiving, it’s important to find ways to relieve that stress. Try mind-body disciplines like yoga and tai chi, more vigorous exercise or practices including mediation and deep breathing.