title: Endogenous opioids inhibit ambulatory blood pressure during naturally occurring stress.
abstract: OBJECTIVE
  Laboratory experiments suggest that endogenous opioids inhibit blood pressure responses during psychological stress. Moreover, there seem to be considerable individual differences in the efficacy of opioid blood pressure inhibition, and these differences may be involved in the expression of risk for cardiovascular disease. To further evaluate the possible role of opioid mechanisms in cardiovascular control, the present study sought to document the effects of the long-lasting oral opioid antagonist naltrexone (ReVia, DuPont, Wilmington, DE) on ambulatory blood pressure responses during naturally occurring stress.
  
  
  METHODS
  Thirty male volunteers participated in a laboratory stress study using naltrexone followed by ambulatory blood pressure under placebo and during the subsequent 24-hour period. Within-subject analyses were performed on ambulatory blood pressures under placebo and naltrexone conditions.
  
  
  RESULTS
  Laboratory results indicate no significant group effects of naltrexone on blood pressure levels or reactivity. Ambulatory results indicate that during periods of low self-reported stress, no effect of opioid blockade was apparent. In contrast, during periods of high stress, opioid blockade increased ambulatory blood pressure.
  
  
  CONCLUSIONS
  These findings suggest that naltrexone-sensitive opioid mechanisms inhibit ambulatory blood pressure responses during naturally occurring stress.
authors.affiliation: Department of Behavioral Science and Anesthesiology, University of Kentucky College of Medicine, Lexington, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: McCubbin
authors.forename: S
authors.initials: S
authors.lastname: Bruehl
authors.forename: J F
authors.initials: JF
authors.lastname: Wilson
authors.forename: J J
authors.initials: JJ
authors.lastname: Sherman
authors.forename: J A
authors.initials: JA
authors.lastname: Norton
authors.forename: G
authors.initials: G
authors.lastname: Colclough
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D018592:Cross-Over Studies; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D009271:Naltrexone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D018847:Opioid Peptides / Q000502:physiology*; D011340:Problem Solving / Q000502:physiology; D013315:Stress, Psychological / Q000139:chemically induced / Q000503:physiopathology*
chemical_list: D009292:Narcotic Antagonists; D018847:Opioid Peptides; D009271:Naltrexone