DISCUSSION Thursday, May 25, 11:00-12:30
Researching the Many Faces of Stress: It's Not Just
in Your Mind
Speakers: Zofia Zukowska, MD, PhD, George Chrousos, MD,
Richard McCarty, PhD, David Goldstein, MD, PhD.
Stress has many faces and yet no definition,
or rather, it has many definitions and none that scientists could agree
upon. The dictionary calls it "a mentally or emotionally disruptive
or upsetting condition occurring in response to adverse external
influences and capable of affecting physical health, usually characterized
by increased heart rate, a rise in blood pressure, muscular tension,
irritability, and depression". Stress has also been called a stimulus
causing such a condition, as well as a state of extreme difficulty,
pressure, or strain. Even without knowing what it is and how and why
it happens, we know when we are stressed. The lack of scientifically
based definition, however, has hampered research. At the same time,
the demands for better understanding and management of stress are mounting,
as stress is escalating worldwide.
The latest wave of terrorism, in particular,
revealed that stress affects people's health not only acutely but also
long-term, increasing incidence of mental, neurodegenerative and cardiovascular
disorders. Even more moderate but chronic psychosocial stress is also
implicated in growing mortality and morbidity from hypertension, coronary
heart disease and stroke, as well as obesity. The latter is of particular
importance as it has risen to epidemic proportion and affected not only
adults but also children. Thus, the issue of stress management has become
of utmost importance, and research into the mechanisms of stress and
anti-stress modalities Ð an urgent mission for the scientific community.
This session will provide a platform for discussion of some of the major
opposing views in stress research, beginning with the time of Hans Selye.
In the first talk, George Chrousos will present
those "Historic Aspects of the Development of the Stress Concepts,"
which led to a reductionist notion that stress can be defined by activation
of the hypothalamic-pituitary-adrenocortical axis (HPA) and the release
of cortisol. This definition has dominated the field for many years,
and to this day, the HPA axis is considered the dominant element of
body's responses to stress. However, the understanding of how it contributes
to development of diseases and how it acts, has changed, and now involves
multiple interactions with other defense mechanisms such as immune system.
In the second talk, Zofia Zukowska will challenge
the dominant role of the HPA axis and take upon herself to present another
reductionist view of "Stress as the Neurogenic Response", and
the critical role of the sympatho-adrenomedullary system. The traditional
Cannon's "fight-and-flight" view of the system will be briefly presented
to be replaced with a modern notion of patterned responses that the
sympathetic nerves and the adrenal medulla elaborate in the face of
different mental and physical stressors. How sympathetic nerves can
elicit such differential responses will be discussed by describing the
complexity of sympathetic neurotransmission, and multiple roles played
by classical neurotransmitters, catecholamines, and the newly discovered
co-transmitter, neuropeptide Y in health and diseases.
Then, Richard McCarty will present the psychologist's
view on "Behavior: the Orphan Child of Stress Research." In it,
he will explain how field of stress research has focused on physiology
and failed to adequately incorporate behavioral variables that are integral
to understanding the links between stress and disease, and how behavioral
variables need to be fully integrated into theoretical perspectives
and research designs to discover the interconnections between stress
and health. Such an integrative approach to stress research requires
a collaborative partnership between biomedical and behavioral scientists.
The last talk, by David Goldstein, will present
a new integrative view of stress. In his "Homeostat Theory,"
he defines stress and distress, and discusses how prolonged activation
of effectors to maintain allostasis during chronic stress contribute
to development of diseases, by entailing decreased functioning of negative
or positive feedback loops. Such a scientific integrative approach forms
a framework of new era medicine, which emphasizes disorders of the multiple
interacting systems that regulate the body's "inner world", explains
diseases in terms of interactions among genetic makeup, life experiences,
drug treatments, and time, with a goal of developing strategies to treat,
prevent, or palliate complex, multi-system, "mind-body" disorders.