The placebo effect and relaxation response: neural processes and their coupling to constitutive nitric oxide

The placebo effect appears to be a real phenomenon as is the scientifically demonstrated and examined relaxation response. Given this, we attempt to u nderstand how these phenomena work in light of our current understanding of central and peripheral nervous system mechanisms. Central to our hypothesi s is the significance of norepinephrine, nitric oxide and opioid signaling both in the central and peripheral nervous system. In this regard, we find that nitric oxide controls norepinephrine processes on many levels, includi ng synthesis, release and actions. In closing, we conclude that enough scie ntific information exists to support these phenomena as actual physical pro cesses that can be harnessed to provide better patient care. (C) 2001 Elsev ier Science B.V. All rights reserved.