title: Nociceptive flexion reflex and pain rating responses during endogenous opiate blockade with naltrexone in healthy young adults.
abstract: The effect of opioid blockade on nociceptive flexion reflex (NFR) activity and subjective pain ratings was examined in 151 healthy young men and women. Using a within-subjects design, NFR threshold was assessed on 2 days after administration of either placebo or a 50mg dose of naltrexone. Electrocutaneous pain threshold and tolerance levels were measured after NFR threshold assessment on each day. Results indicated that administration of naltrexone was consistently associated with hypoalgesic responding. Specifically, participants exhibited lower levels of NFR activity and reported lower pain ratings for electrocutaneous stimulation delivered at pain threshold and tolerance levels following administration of naltrexone as compared to placebo. These findings indicate that opiate blockade using the current standard dose may elicit hypoalgesia. A potential moderating effect of dose of opiate-blockade medication and level of endogenous opioid activation should be carefully examined in future research.
authors.affiliation: Department of Psychology, Ohio University, Athens, OH 45701, USA. France@ohio.edu
authors.forename: Christopher R
authors.initials: CR
authors.lastname: France
authors.forename: Mustafa
authors.initials: M
authors.lastname: al'Absi
authors.forename: Christopher
authors.initials: C
authors.lastname: Ring
authors.forename: Janis L
authors.initials: JL
authors.lastname: France
authors.forename: Angie
authors.initials: A
authors.lastname: Harju
authors.forename: Lorentz E
authors.initials: LE
authors.lastname: Wittmers
mesh_terms: D000293:Adolescent; D000328:Adult; D004311:Double-Blind Method; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D009271:Naltrexone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D018847:Opioid Peptides / Q000037:antagonists & inhibitors*; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects*; D012026:Reflex, Stretch / Q000187:drug effects*
chemical_list: D009292:Narcotic Antagonists; D018847:Opioid Peptides; D009271:Naltrexone