Epinephrine suppresses stress-induced increases in plasma immunoreactive beta-endorphin in humans.
The present study evaluated the hypothesis that increased plasma levels of epinephrine (EPI) stimulate immunoreactive beta-endorphin (i beta END) secretion in humans experiencing a mild stress. The stressor consisted of intraoral injections of a local anesthetic solution (with or without EPI) just before the surgical extraction of impacted third molars in 26 awake unsedated patients. The EPI group experienced a 30-fold increase in plasma EPI levels by 2 min after injection; these concentrations were physiologically active, as evidenced by increased pulse rate and systolic blood pressure. However, compared to a no EPI control group the EPI group had a significantly reduced i beta END response to the stressor, as evaluated by comparison of plasma levels at individual time points, maximal increases in plasma i beta END levels, and areas under the time-response curve. Whereas there was no association between plasma levels of EPI and i beta END in the EPI group (r = 0.119; P = NS), EPI and i beta END levels were strongly related in the no EPI group (r = 0.82; P less than 0.001). These results do not support the hypothesis of a stimulatory effect for EPI on i beta END release and, instead, suggest that an inhibitory relationship may exist in humans experiencing stress. The association between EPI and i beta END responses observed in the control group during this form of stress appears to be due to activation of a common central neural element.
Troullos
E S
ES
Neurobiology and Anesthesiology Branch, National Institute of Dental Research, Bethesda, Maryland 20892.
Hargreaves
K M
KM
Goldstein
D S
DS
Stull
R
R
Dionne
R A
RA
D000779:Anesthetics, Local; D001794:Blood Pressure / Q000187:drug effects; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D004837:Epinephrine / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000097:blood; D011674:Pulse / Q000187:drug effects; D013315:Stress, Psychological / Q000503:physiopathology*; D014081:Tooth Extraction; D001615:beta-Endorphin / Q000097:blood / Q000378:metabolism*
D000779:Anesthetics, Local; D001615:beta-Endorphin; D009638:Norepinephrine; D004837:Epinephrine