Sodium Has New Role in the Brain

MONTREALSodiumthe main chemical component in table saltis a unique on/off" switch for a major neurotransmitter receptor in the brain, according to new research conducted at McGill University.

This receptor, known as the kainate receptor, is fundamental for normal brain function and is implicated in numerous diseases, such as epilepsy and neuropathic pain.

Balancing kainate receptor activity is the key to maintaining normal brain function. For example, in epilepsy, kainate activity is thought to be excessive. Thus, drugs which would shut down this activity are expected to be beneficial.

It has been assumed for decades that the on/off" switch for all brain receptors lies where the neurotransmitter binds," says Professor Derek Bowie, lead researcher. However, we found a completely separate site that binds individual atoms of sodium and controls when kainate receptors get turned on and off."

The research shows how the brain transmits information and highlights new drug development possibilities.

The sodium switch is unique to kainate receptors, which means that drugs designed to stimulate this switch, should not act elsewhere in the brain. This would be a major step forward, since drugs often affect many locations, in addition to those they were intended to act on, producing negative side-effects as a result. These so called off-target effects" for drugs represent one of the greatest challenges facing modern medicine.

Now that we know how to stimulate kainate receptors, we should be able to design drugs to essentially switch them off," says Bowie.