Hampshire scientists are to launch a major study of little-known proteins they believe are a contributing factor to diseases such as dementia and multiple sclerosis.

The team of biologists at the University of Portsmouth have been awarded £600,000 to research the impact on the ageing of the brain and cognitive decline.

The study will focus on a protein known as Kir4.1 which is a key element in controlling special cells in the brain and spinal cord which form myelin, a substance which insulates the brain's wiring.

They discovered that the protein is critical in ensuring these cells, known as oligodendrocytes, function well.

The researchers already know that myelin acts as the insulating layer around nerve cells and is essential for rapid conduction of information and when it is damaged this interferes with messages between the brain and other parts of the body.

They are also researching another protein called Gas6 which they have discovered can stimulate oligodendrocyte production and survival.

The team's combined research will focus on signals in the brain which stimulate the growth and regeneration of oligodendrocytes and myelin.

Professor Arthur Butt, from the School of Pharmacy and Biomedical Sciences, said: ''These cells in the brain are generated at birth and during the first years of development.

''But they continue to be generated in the adult brain and are important for replacing cells lost during the normal ageing process.

''We think that the brain slows down its production of these cells as it ages and this decreases the rate at which the brain repairs its white matter - important for cognitive function.

''The area of the brain known as the hippocampus, important for storing memory, is also affected.

''Through investigating the signals used by the brain to control these functions we hope to gain further insight into the ageing brain and better understand diseases such as Alzheimer's and dementia.''

The research, funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and the Multiple Sclerosis (MS) Society, will start later this year and take three years to complete.

The scientists hope the results could be used to develop experimental treatments for diseases of the brain and MS, and also contribute to future diagnostic tools for clinicians to predict Alzheimer's and dementia.