Sodium channels affect cognitive decline in aging brains

Thursday 02 February 2012

Neuroscientists at the University of Bristol, led by Prof Andy Randall and Dr. Jon Brown, have found a mechanism that may cause cognitive decline during normal healthy aging.

The brain mainly uses electrical signals called action potentials to encode and convey information. In this study, researchers concentrated on the action potentials that are created in neurons of the hippocampus. They made recordings of electrical signals in order to track neuronal excitability, i.e. the ability to produce action potentials.

Results showed that aged neurons find it more difficult to generate action potentials – and that this reluctance is due to changes in the properties of sodium channels. Sodium channels are proteins which affect the creation of action potentials by controlling the flow of sodium ions into neurons.

Prof Randall, Professor in Applied Neurophysiology said: "Much of our work is about understanding dysfunctional electrical signalling in the diseased brain, in particular Alzheimer's disease. We began to question, however, why even the healthy brain can slow down once you reach my age. Previous investigations elsewhere have described age-related changes in processes that are triggered by action potentials, but our findings are significant because they show that generating the action potential in the first place is harder work in aged brain cells." This research project is funded by Pfizer.

www.neurobiologyofaging.org/article/S0197-4580(11)00575-6/abstract