Revisiting convergence; automaticity (Introduction)

by David Turell , Thursday, June 25, 2015, 19:20 (3438 days ago) @ David Turell

this article shows how automatic the body is to perceived danger; flight or fight starts with adrenaline and the heart responds with calcium uptake by the mitochondria, supplying power for the reaction:-http://medicalxpress.com/news/2015-06-calcium-uptake-mitochondria-heart-harder.html-"In a life-threatening situation, the heart beats faster and harder, invigorated by the fight-or-flight response, which instantaneously prepares a person to react or run. Now, a new study by researchers at Temple University School of Medicine (TUSM) shows that the uptick in heart muscle contractility that occurs under acute stress is driven by a flood of calcium into mitochondria—the cells' energy-producing powerhouses.-"In the fight-or-flight response, the release of adrenaline activates numerous systems in the body to prepare for the perceived stress. A key aspect of this response is an increase in cardiac contractility. Adrenaline increases calcium cycling in the heart to drive contraction. That same calcium enters mitochondria through a channel known as the mitochondrial calcium uniporter (MCU). Dr. Elrod and colleagues at TUSM and Cincinnati Children's Hospital have been investigating MCU since its discovery in 2011, attempting to elucidate its function specifically in heart muscle cells.-"As part of their work, they knocked out, or removed, MCU from mitochondria in the hearts of adult mice. In doing so, they discovered that in mice lacking MCU, the heart failed to respond to adrenaline-receptor stimulation with isoproterenol—an adrenaline-like chemical that in high doses normally sends the heart into overdrive, mimicking aspects of the fight-or-flight response."