یک چشم انداز جدی درباره استرس: تمرکزی بر میتوکندری An energetic view of stress: Focus on mitochondria

1. Introduction Life emerges when biological structures are animated by energy. Energy is defined as a fundamental entity of nature that is transferred between parts of a system in the production of physical change within the system, and usually regarded as the capacity for doing work (Merriam-Webster, 2017). Without energy, there is no life – molecules alone do not interact in meaningful ways, and complex structures do not assemble nor replicate. A crucial factor that distinguishes the breathing-living organism from the inanimate body (i.e., cadaver) is the flow of energy. There are no intrinsic differences in the molecular composition of dead and living organisms. But it is a required quality of living organisms to experience a constant flow of energy through and between their different parts. This flow of energy sustains the movement, chemical reactions, and dynamic changes in the position and organization of molecules that is required to think, feel, move, and execute every element of the stress response. Without energy, stress adaptation is not possible, and the body dies. This review discusses the concept of stress as an energy-dependent and coordinated process, with an emphasis on the key role that mitochondria plays in these processes. With a broad view of energy, we take a multi-level approach exploring the role of mitochondria in glucocorticoid and catecholamine metabolism, and the effects of stress hormones on energy substrate distribution within the body. We also consider the reciprocal action of steroid hormones on mitochondria. The influence of stress on food/energy-seeking behavior and emerging evidence regarding the influence of mitochondrial functions on mental health, social behaviors, and physiological stress reactivity are also discussed. An energetic view of stress adaptation and pathophysiology opens new possibilities to rationalize and investigate the integrated adaptive and maladaptive effects of stress on the brain and body