Dietary capsaicin - the active ingredient in chillis - produces chronic activation of a receptor on cells that line the intestines of mice, triggering a reaction that ultimately reduces the risk of colorectal tumours, say researchers at the University of California, San Diego School of Medicine. The findings were published in . The receptor, or ion channel, called TRPV1 was discovered in sensory neurons, where it acts as a sentinel for heat, acidity and spicy chemicals in the environment. "These are potentially harmful stimuli to cells," says Eyal Raz, professor of medicine. "Thus, TRPV1 was quickly described as a molecular pain receptor. This can be considered to be its conventional function, which takes place in the nervous system."
Preventing weight gain, obesity and, ultimately, diabetes could be as simple as keeping a nuclear receptor from being activated in a part of the brain, according to a study by Yale School of Medicine researchers. Published in the , the study showed that when researchers blocked the effects of the nuclear receptor PPARgamma in a small number of brain cells in mice, the animals ate less and became resistant to a high-fat diet. "These animals ate fat and sugar, and did not gain weight, while their control littermates gained weight on the same diet," says Sabrina Diano, professor of obstetrics, gynecology and reproductive sciences at Yale. "We showed that the PPARgamma receptor in neurons that produce POMC could control responses to a high-fat diet without resulting in obesity." POMC neurons regulate food intake.
Johns Hopkins researchers say they have discovered a chemical alteration in a single human gene linked to stress reactions that, if confirmed in larger studies, could allow doctors to reliably predict a person's risk of attempting suicide with a simple blood test. The discovery, described online in the , suggests that changes in a gene involved in the function of the brain's response to stress hormones play a significant role in turning what might otherwise be an unremarkable reaction to the strain of everyday life into suicidal thoughts and behaviour. "Suicide is a major preventable public health problem, but we have been stymied in our prevention efforts because we have no consistent way to predict those who are at increased risk of killing themselves," says study leader Zachary Kaminsky, an assistant professor at Johns Hopkins.
