Researchers in the Hotchkiss Brain Institute (HBI) at the University of Calgary's Faculty of Medicine have uncovered a mechanism by which stress increases food drive in rats. This new discovery could provide important insight into why stress is thought to be one of the underlying contributors to obesity.
Normally, the brain produces neurotransmitters (chemicals responsible for how cells communicate in the brain) called endocannabinoids that send signals to control appetite. In this study, the researchers found that when food is not present, a stress response occurs that temporarily causes a functional re-wiring in the brain. This re-wiring may impair the endocannabinoids'' ability to regulate food intake and could contribute to enhanced food drive, the researchers said.The researchers also discovered that when they blocked the effects of stress hormones in the brain, the absence of food caused no change in the neural circuitry. Researchers Jaideep Bains, Ph.D. and Quentin Pittman, Ph.D., looked specifically at nerve cells (neurons) in the region of the brain called the hypothalamus. This structure is known to have an important role in the control of appetite and metabolism and has been identified as the primary region responsible for the brain''s response to stress.
“These findings could help explain how the cellular communication in our brains may be overridden in the absence of food,” Bains said. “Interestingly, these changes are driven not necessarily by the lack of nutrients, but rather by the stress induced by the lack of food,” he added. The study was recently published in the journal Neuron.