Biology Reference
In-Depth Information
Figure 11.2
The description on the complexity of the brain written by Ivan Pavlov in his topic
“Conditioned reflexes: An investigation of the physiological activity of the cerebral cortex”
published in 1927.
Hans Selye's approach was quite different, starting with his clinical observations
during his medical studies in Prague in the 1920-30s. He noticed how severely sick
or badly traumatized patients often exhibited closely similar symptoms, independent
of insult, including signs of adrenocortical enlargement and atrophy of lymphatic tis-
sues. Emigrating to Montreal, he later got the opportunity to test his observations on
patients in laboratory animals and gradually it became clear that an intense engage-
ment of the hypophyseal-glucocortiocoid system was a key link in explaining his
findings. In 1936, Selye introduced “the syndrome that was produced by diverse noc-
uous stimuli”
[17]
, though unfortunately he labelled the observed syndrome “stress”.
The term “strain” would, however, have been more-to-the-point as stress causes
strain, like these terms are used in the field of physics. Actually, Selye later said jok-
ingly that had his English been better in younger years, he would have been world
known as “father of strain” instead of “father of stress”
[19]
.
Thus, while Cannon and Hess emphasized the hypothalamic-sympatho-adrenomed-
ullary axis as a major cerebral command link, Selye's work was of key importance for
revealing the equally important hypothalamic-pituitary-adrenocortical axis (HPA-axis).
These pioneer findings of Selye started a new research field and over the past half cen-
tury the glucocortiocoid (GC) effects have been intensely studied, revealing that their
roles are much more complex than Selye may have thought. Thus, the GC action in
stress is a picture of extraordinary diversity, depending on the physiological endpoints,
and later research has shown that GC effects can act both suppressive and stimulatory as
well as permissive, depending on situation, timeframe and which organ is affected
[20]
.
An important part of this diversity was published by Hench and co-workers already in
1949 when they showed the remarkable anti-inflammatory action of GC
[21]
, which
