Pituitary-adrenal response to naloxone in non-ulcer dyspepsia: preliminary evidence for a reduction in central opioid tone.
BACKGROUND
Non-ulcer dyspepsia (NUD) is one of the core functional bowel disorders. There has been recent emphasis on possible abnormal brain-gut interactions as being central to its pathophysiology. In this preliminary study, we examined central opioid tone in Helicobacter pylori-negative NUD patients using naloxone, an opioid antagonist, which stimulates pituitary-adrenal activity. The opioid system is known to govern nociceptive processing and to play a role in gut motor activity.


METHODS
Eight subjects with NUD and 8 age- and sex-matched healthy subjects were examined.


METHODS
Naloxone, 0.125 mg/kg, was administered at time 0. Adrenocorticotropin (ACTH) and cortisol responses were measured over a 120-min period. Maximum pituitary-adrenal responses in the 2 groups were compared.


RESULTS
The ACTH response was significantly attenuated in the NUD group (p < 0.05). The cortisol response did not differ between the 2 groups (p = 0.7).


CONCLUSIONS
Central opioid tone may be reduced in subjects with NUD. Our preliminary findings suggest that altered opioidergic activity may contribute to NUD pathophysiology, influencing the symptom profile through altered gut motor activity or possibly by influencing visceral sensitivity.
Scott
Lucinda V
LV
Department of Psychiatry, Cork University, Wilton, Cork, Ireland. lucinda@gofree.indigo.ie
Rathore
Omar
O
Dinan
Timothy G
TG
Keeling
P W N
PW
D000324:Adrenocorticotropic Hormone / Q000096:biosynthesis; D000328:Adult; D016022:Case-Control Studies; D004415:Dyspepsia / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000096:biosynthesis; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D010913:Pituitary-Adrenal System / Q000187:drug effects* / Q000502:physiology
D009292:Narcotic Antagonists; D009270:Naloxone; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone