Neurobiology and inflammatory arthritis.

As diagrammed in Figures 1 and 2, the central and peripheral nervous systems, the endocrine system, and immune and inflammatory systems are extensively integrated. The boundaries defining these systems are both anatomically and molecularly blurred. This realization has been driven by the ongoing revolution in molecular biology. Normally the deleterious effects of excessive or persistent inflammation are prevented by homeostatic neuroendocrine feedback loops. Conversely, dysfunction in these counter-regulatory responses may lead to important clinical phenomena such as autoimmunity and chronic inflammation in association with behavioral alterations such as fatigue, depressed mood, and loss of libido. Continued research into the neurobiology of inflammation appears likely to explain some of the fundamental abnormalities in diseases such as RA and lead to new, more effective therapies.