人體可藉由壓力感受器(baroreceptor)的感壓反射(baroreflex)來感受血壓瞬間變化並在短時間內調整之以維持相對穩定的生理狀態,自主神經系統(autonomic nervous system)參與此運作。中醫理論裡“並精出入謂之魄”,“魄”隨精血敷布輸注體表、四肢及內臟腑;外能接受外界刺激,覺痛癢,辨音色,內可助呼吸心跳、氣血運行,就功能上,“魄”可以視為本能反應及自主神經系統的自我調節系統,是不受內在意識所支配的本能作用。本文藉由探討壓力感受器在恐慌發作(panic attack)、高血壓(hypertension)及姿態性低血壓(orthostatic hypotension、postural hypotension)幾種疾病中所扮演的生理病理學角色,對照其在中醫學上的病理機轉論述,進而推論認為壓力感受器所表現的功能相類於中醫理論中“魄”的角色,是可以在無意識(unconscious)下維持生理上穩定的動態平衡。
The human body can perceive instantaneous changes in blood pressure through the baroreflex of the baroreceptors and adjust it within a short time to maintain a relatively stable physiological state. The autonomic nervous system is involved in this operation. In the theory of traditional Chinese medicine, "Po`" is coming in and out of the essence of the body simultaneously. The "Po`" follows the essence and blood to spread and infuse the body surface, limbs, and internal organs. Externally, "Po`" can receive outer stimulations, feel pain and itch, and distinguish sounds and colors. Internally, it helps breathing, heart beating, and blood circulating. In terms of functional performance, the "Po`" can be considered as the self-regulation system of instinctive response as well as the autonomic nervous system, and instinctive actions not dominated by internal consciousness. Through the exploration of the roles of baroreceptors in pathophysiology of diseases including panic attacks, hypertension, and postural hypotension and comparison with the corresponding pathological mechanisms in traditional Chinese medicine, we deduce that the function of baroreceptors is similar to the role of "Po`" in the theory of traditional Chinese medicine, which can unconsciously maintain a stable dynamic balance in physiology.