情動による循環調節のリセッティング

抄録

The word "homeostasis" implies a regulatory mechanism that stabilizes the biological parameters around an operating point during the resting condition. During exercise or stressful condition, however, a new operating point will be set. This operating point is different from that under the resting condition and should be suitable for the bodily demand during the new condition. To explore neural mechanisms of such resetting of the operating point, we have recently focused on the stress-induced defense response because stressor induces not only cognitive, emotional and behavioral changes but also autonomic changes. These changes include increases in blood pressure, heart rate, muscular blood flow, respiratory frequency, and tidal volume and suppression of the baroreceptor reflex and pain sensitivity. Although research on the neural circuits underlying such autonomic changes has implicated the hypothalamus in the defense response against stressors, neurotransmitters in this multifacet and coordinated response have not been revealed. In my talk, I will summarize our recent discovery of possible contribution of orexin as a master switch to elicit multiple efferent pathways in the defense response and discuss future directions. [J Physiol Sci. 2006;56 Suppl:S26]