Hunger hormone also involved in memory and learning
the memory, Scottish scientists will reveal today.
The researchers from Dundee University have found a link between the hormone leptin and the brain's memory and learning process.
The findings could help explain how obesity affects learning and memory.
Previous studies have found that people who are obese throughout life are more likely to lose brain tissue, and scientists have already predicted that the current obesity epidemic will give rise to a major increase in dementia.
Almost one third of people living in the European Union are overweight and more than one in ten is now obese, according to European Association for the Study of Obesity. These numbers are set to increase further in an ageing population, with a high prevalence of childhood obesity.
Speaking at the annual BioScience conference, being held in Glasgow this week, the scientists note that there is already much evidence to show how the hormone leptin signals information regarding the status of fat stores to specific receptors located in the hypothalamus region of the brain. This controls our desire to eat, and therefore, our body weight.
But leptin and its receptor are widely expressed in many brain regions outside the hypothalamus and evidence is accumulating that it has other neuronal functions that are unrelated to its effects on energy homeostasis.
This includes research showing that leptin has a significant influence on learning and memory processes in the hippocampus region.
Jenni Harvey, one of the Dundee researchers, told the BBC: "Leptin enhances the level of communication between brain cells in the hippocampus in a process known as long-term potentiation (LTP). Defects in either leptin or genes that regulate leptin result in obesity and also cause impairments in LTP."
The team is currently examining the precise mechanisms that are responsible for the effects of leptin on LTP.
Earlier studies have found that leptin-deficient rodents display abnormalbrain development. It has also been demonstrated that administering leptin into the dentate gyrus can facilitate hippocampal long-term potentiation (LTP) in vivo, and improve memory processing in mice, say the Scottish researchers.
