Emotional Modification of the Cardiorespiratory Regulation System

Our daily life is not solely composed of a calm resting state but is rather full of perturbations that induce active states such as moving, eating, communicating, and so on. During such active conditions, cardiorespiratory regulation should be adjusted according to the body's demand, which differs from that during a resting state, by modulating or resetting the operating point. To explore the neural mechanisms of state-dependent adjustment of central autonomic regulation, we focused on the stress-induced defense (fight-or-flight) response because stressors induce not only cognitive, emotional and behavioral changes but also autonomic changes. In this mini-review, we summarize our recent discovery using orexin knockout mice and orexin neuron-ablated mice of the possible contribution of orexin, a hypothalamic neuropeptide, in the state-dependent adjustment of central autonomic regulation. The diversity of synaptic control of the cardiovascular and respiratory neurons seems necessary for animals to adapt themselves toward ever-changing life circumstances and behavioral states. The orexin system is likely to work as one of the essential modulators for coordinating circuits controlling autonomic functions and behavior.