Forceful heart, lung, metabolic and behavioral reactions help cope with acute threats, McCobb says, "but those reactions are not healthful in the long run. We found that steroid stress hormones dictate whether the potassium channels controlling adrenaline release are constructed with or without an optional piece called STREX, for stress exon. This STREX exon causes the channel to open more easily, which favors rapid, excitable responses and fast secretion of adrenaline."
To test the theory, the Cornell researchers surgically removed several rats' pituitary glands, the source of ACTH (adrenocorticotropic hormone), a key link in the stress hormone cascade. Without pituitary glands, the percentage of STREX-type channels dropped sharply. This was prevented by injecting ACTH artificially.
The Science article is entitled, "Control of Alternative Splicing of Potassium Channels by Stress Hormones."