Zebrafish Study Finds A Unique On-Off Switch For Hormone Production Which Likely Exists In The Human Brain
After we sense a threat, our brain center responsible for responding goes into gear, setting off a chain of biochemical reactions leading to the release of cortisol from the adrenal glands. Dr. Gil Levkowitz and his team in the Molecular Cell Biology Department have now revealed a new kind of ON-OFF switch in the brain for regulating the production of a main biochemical signal from the brain that stimulates cortisol release in the body. This finding, which was recently published in Neuron, may be relevant to research into a number of stress-related neurological disorders. This signal is corticotropin releasing hormone (CRH). CRH is manufactured and stored in special neurons in the hypothalamus. Within this small brain region the danger is sensed, the information processed and the orders to go into stress-response mode are sent out.
If stress is giving you high blood pressure, blame the immune system. T cells, helpful for fighting infections, are also necessary for mice to show an increase in blood pressure after a period of psychological stress, scientists have found. The findings suggest that the effects of chronic stress on cardiovascular health may be a side effect of having an immune system that can defend us from infection. The results also have potential implications for treating both high blood pressure and anxiety disorders. The results are published in the journal Biological Psychiatry. "Chronic stress has long been known to have harmful effects on the immune system as well as being a risk factor for hypertension, " says lead author Paul Marvar, a postdoctoral fellow at Emory University School of Medicine.
In low- and middle-income countries, mild cognitive impairment - an intermediate state between normal signs of cognitive aging, such as becoming increasingly forgetful, and dementia, which may or may not progress - is consistently associated with higher disability and with neuropsychiatric symptoms but not with most socio-demographic factors, according to a large study published in this week's PLoS Medicine. The established 10/66 Dementia Research Group interviewed approximately 15 000 people over 65 years of age who did not have dementia in eight low- and middle-incomes countries: Cuba, Dominican Republic, Peru, Mexico, Venezuela, Puerto Rico, China, and India. Participants also completed standardized assessments of their mental and physical health and cognitive function and the researchers also interviewed relatives and carers for further details about any memory loss or other declines in cognitive function or the presence of any neuropsychiatric symptoms.
Researchers measured people's physical and psychological responses while they used Facebook, performed a stressful task, or just relaxed, and found each of these activities appears to have a different effect on mood and arousal. Dr. Maurizio Mauri of the Institute of Human, Language and Environmental Sciences at IULM University in Milan, Italy, and colleagues, write about their findings in the peer-reviewed journal Cyberpsychology, Behavior, and Social Networking. A press statement on the study was released earlier this week. In their background information, the researchers explain that few studies have tried to find out which aspects of the social networking experience makes sites like Facebook so successful, although it is known that their use can have both positive and negative effects.
Older adults who sleep poorly have an altered immune system response to stress that may increase risk for mental and physical health problems, according to a study led by a University of Rochester Medical Center researcher. In the study, stress led to significantly larger increases in a marker of inflammation in poor sleepers compared to good sleepers - a marker associated with poor health outcomes and death. "This study offers more evidence that better sleep not only can improve overall well-being but also may help prevent poor physiological and psychological outcomes associated with inflammation, " said Kathi L. Heffner, Ph.D., assistant professor of Psychiatry at the Medical Center. The association between poor sleep and a heightened inflammatory response to acute stress could not be explained by other factors linked to immune impairment, including depression, loneliness and perceived stress, the researchers said in the study published by the American Journal of Geriatric Psychiatry.