How the ‘fight-or-flight’ reaction hinders cellular defense mechanisms
Research from the lab of Mark Alkema, PhD, teacher of neurobiology, clarifies how the “flight-or-flight” action impairs long-term organism health. The research study, carried out in the nematode worm, C. elegans, a typical research model, was released in Nature.
When people view an unsafe or demanding situation, the body launches tension hormonal agents such as adrenalin. Adrenaline makes the heart beat quicker, increases blood circulation to the brain and muscles, and stimulates the body to make sugar to utilize for fuel. The rush of adrenaline activates the “fight-or-flight” action which gives the person the capability to escape a predator or respond to a threat.
Dr. Alkema, working with the laboratory of Teacher Diego Rayes at the National University of South in Argentina, studied the effect of the repeated activation of the “fight-or-flight” action on health in the nematode C. elegans. This little worm is a popular model organism that has actually assisted solve many basic concerns in biology, varying from development to brain function and illness.
Animals are exposed to different kinds of tension. These can be abrupt, such as the appearance of a predator, or more progressive, like chronic food shortage, high temperatures, or oxidation.
“Much like in humans, repeated activation of the flight response in C. elegans drastically shortened lifespan,” said Jeremy Florman, PhD candidate in the Alkema lab. “The flight response is crucial for the worm to escape from predators. But we find there is a cost; the repeated activation of the flight response reduces the worm’s capacity to deal with other challenges it encounters in its environment.”
In the research study, investigators discovered that the flight response in C. elegans sets off the activation of a single pair of neurons that release tyramine, the invertebrate analog of adrenaline. In contrast, direct exposure to ecological obstacles such as heat and oxidative tension minimizes tyramine release. This tension hormonal agent hence offers a switch that manages the animal’s response to either severe or long-lasting stressors.
Alkema and Rayes went on to reveal that tyramine stimulates the insulin pathway through the activation of an adrenergic-like receptor in the intestine. The activation of the insulin path can please the animal’s energy needs of the flight action. On the other hand, the down-regulation of the insulin path is needed aid to safeguard cells from ecological stress and extend life-span.
“This shows how a dynamic regulation of a stress neurohormone regulates the trade-off between acute and long-term stress responses,” said Alkema. “The worm never ceases to amaze me; it keeps revealing fundamental molecular and neural mechanisms that may underlie even extremely complex human biology and disorders. Given the striking conservation of stress response mechanisms from worms to humans, it will be very interesting to see whether in humans the fight-or-flight response and stress neurohormones negatively impact health and aging through the activation of the insulin pathway.”