Structure and Function Relationships Between the Neuroendocrine and Immune System; Stress as a Factor in Disease Susceptibility
B.W. Fenwick, DVM, MS, PhD
Empirical data strongly supports the interaction between the nervous
system and susceptibility to disease. During periods of psychological stress the incidence of
both mild and severe disease increases significantly. While these findings provide evidence of
the ability of the nervous system to influence immune function there is also a growing body of
data that indicates that the immune system nay also effect neuroendocrine function.
Regulation of both the neuroendocrine and immune system is in large part via
secondary messengers (hormones and lymphokines) whose production and secretion mediate activity
of specific cells. The functional interactions between the neuroendocrine and immune system is
evidenced by the ability of several neuroendocrine hormones to influence (both positively and
negatively) immunologic functions and by the production of neuroendocrine hormones by stimulated
lymphocytes. In many cases, this "cross-talk" appears to be the consequence of the
production of secondary messengers common to both the immune and neuroendocrine systems.
As our understanding of the interrelationships between the immune and
neuroendocrine systems increases, a more accurate picture of the interactions between these
systems will merge. The implications and potential usefulness of this information will be to
allow a determination of when physiologic or environmental stressors detrimentally alter the
defense systems that are responsible for providing protection from disease.