{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T12:25:56Z","timestamp":1768998356396,"version":"3.49.0"},"reference-count":59,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2011,12,19]],"date-time":"2011-12-19T00:00:00Z","timestamp":1324252800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["European Journal of Pain"],"published-print":{"date-parts":[[2012,3]]},"abstract":"Abstract<\/jats:title>Plasma levels of beta\u2010endorphin (BE<\/jats:styled-content>), an endogenous opioid analgesic, are often reported as they relate to acute and chronic pain outcomes. However, little is known about what resting plasma BE<\/jats:styled-content> levels might reveal about functioning of the endogenous opioid antinociceptive system. This study directly examined associations between resting plasma BE<\/jats:styled-content> and subsequent endogenous opioid analgesic responses to acute pain in 39 healthy controls and 37 individuals with chronic low back pain (LBP<\/jats:styled-content>). Resting baseline levels of plasma BE<\/jats:styled-content> were assessed. Next, participants received opioid blockade (8\u2009mg naloxone i.v.) or placebo in a double\u2010blind, randomized, crossover design. Participants then underwent two acute pain stimuli: finger pressure (FP<\/jats:styled-content>) pain and ischaemic (ISC<\/jats:styled-content>) forearm pain. Blockade effects (naloxone minus placebo pain ratings) were derived to index endogenous opioid analgesic function. In placebo condition analyses for both pain stimuli, higher resting BE<\/jats:styled-content> levels were associated with subsequently greater reported pain intensity (p<\/jats:italic>'s<\/jats:styled-content>\u2009<\u20090.05), with this effect occurring primarily in healthy controls (BE<\/jats:styled-content>\u2009\u00d7\u2009P<\/jats:styled-content>articipant T<\/jats:styled-content>ype interactions, p<\/jats:italic>'s<\/jats:styled-content>\u2009<\u20090.05). In blockade effect analyses across both pain tasks, higher resting plasma BE<\/jats:styled-content> predicted less subsequent endogenous opioid analgesia (smaller blockade effects; p<\/jats:italic>'s<\/jats:styled-content>\u2009<\u20090.05). For the ISC<\/jats:styled-content> task, these links were significantly more prominent in LBP<\/jats:styled-content> participants (BE<\/jats:styled-content>\u2009\u00d7\u2009P<\/jats:styled-content>articipant T<\/jats:styled-content>ype I<\/jats:styled-content>nteractions, p<\/jats:italic>'s<\/jats:styled-content>\u2009<\u20090.05). Results suggest that elevated resting plasma BE<\/jats:styled-content> may be a potential biomarker for reduced endogenous opioid analgesic capacity, particularly among individuals with chronic pain. Potential clinical implications are discussed.<\/jats:p>","DOI":"10.1002\/j.1532-2149.2011.00021.x","type":"journal-article","created":{"date-parts":[[2011,12,22]],"date-time":"2011-12-22T11:38:15Z","timestamp":1324553895000},"page":"370-380","source":"Crossref","is-referenced-by-count":48,"title":["What do plasma beta\u2010endorphin levels reveal about endogenous opioid analgesic function?"],"prefix":"10.1002","volume":"16","author":[{"given":"S.","family":"Bruehl","sequence":"first","affiliation":[{"name":"Department of Anesthesiology Vanderbilt University School of Medicine Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J.W.","family":"Burns","sequence":"additional","affiliation":[{"name":"Department of Behavioral Science Rush University Chicago IL USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"O.Y.","family":"Chung","sequence":"additional","affiliation":[{"name":"Department of Anesthesiology Vanderbilt University School of Medicine Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M.","family":"Chont","sequence":"additional","affiliation":[{"name":"Department of Anesthesiology Vanderbilt University School of Medicine Nashville TN USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2011,12,19]]},"reference":[{"key":"e_1_2_6_2_1","volume-title":"Multiple regression: testing and interpreting interactions","author":"Aiken LS","year":"1991"},{"key":"e_1_2_6_3_1","doi-asserted-by":"publisher","DOI":"10.1097\/01.psy.0000116250.81254.5d"},{"key":"e_1_2_6_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0304-3959(02)00103-3"},{"key":"e_1_2_6_5_1","doi-asserted-by":"publisher","DOI":"10.3109\/00365518709168942"},{"key":"e_1_2_6_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/0304-3959(92)90257-C"},{"key":"e_1_2_6_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0306-4530(97)00053-X"},{"key":"e_1_2_6_8_1","volume-title":"Outliers in statistical data","author":"Barnett V","year":"1994"},{"key":"e_1_2_6_9_1","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.ne.07.030184.001521"},{"key":"e_1_2_6_10_1","doi-asserted-by":"publisher","DOI":"10.1001\/archpsyc.1961.01710120031004"},{"key":"e_1_2_6_11_1","doi-asserted-by":"publisher","DOI":"10.1093\/cercor\/bhn013"},{"key":"e_1_2_6_12_1","doi-asserted-by":"publisher","DOI":"10.1097\/PSY.0b013e3181baef05"},{"key":"e_1_2_6_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0304-3959(01)00451-1"},{"key":"e_1_2_6_14_1","doi-asserted-by":"publisher","DOI":"10.1097\/PSY.0b013e318227cb88"},{"key":"e_1_2_6_15_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0304-3959(02)00104-5"},{"key":"e_1_2_6_16_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.pain.2006.04.018"},{"key":"e_1_2_6_17_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.pain.2006.11.013"},{"key":"e_1_2_6_18_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.pain.2009.09.025"},{"key":"e_1_2_6_19_1","doi-asserted-by":"publisher","DOI":"10.1097\/00002508-200409000-00002"},{"key":"e_1_2_6_20_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0149-7634(99)00039-1"},{"key":"e_1_2_6_21_1","doi-asserted-by":"publisher","DOI":"10.1038\/270620a0"},{"key":"e_1_2_6_22_1","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.34.3.378"},{"key":"e_1_2_6_23_1","doi-asserted-by":"publisher","DOI":"10.1016\/0165-1781(82)90032-4"},{"key":"e_1_2_6_24_1","doi-asserted-by":"publisher","DOI":"10.1067\/mcp.2001.116443"},{"key":"e_1_2_6_25_1","doi-asserted-by":"publisher","DOI":"10.1016\/0735-1097(93)90585-O"},{"key":"e_1_2_6_26_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-8986.1971.tb00441.x"},{"key":"e_1_2_6_27_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.biopsycho.2006.12.005"},{"key":"e_1_2_6_28_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.pain.2008.11.014"},{"key":"e_1_2_6_29_1","doi-asserted-by":"publisher","DOI":"10.1038\/306264a0"},{"key":"e_1_2_6_30_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0735-1097(96)00312-9"},{"key":"e_1_2_6_31_1","first-page":"E235","article-title":"The role of pituitary beta\u2010endorphin in mediating corticotropin\u2010releasing factor\u2010induced antinociception","volume":"258","author":"Hargreaves KM","year":"1990","journal-title":"Am J Physiol"},{"key":"e_1_2_6_32_1","doi-asserted-by":"publisher","DOI":"10.1038\/clpt.1987.206"},{"key":"e_1_2_6_33_1","doi-asserted-by":"publisher","DOI":"10.1007\/s12020-009-9163-5"},{"key":"e_1_2_6_34_1","doi-asserted-by":"publisher","DOI":"10.1001\/archpsyc.63.11.1199"},{"key":"e_1_2_6_35_1","doi-asserted-by":"publisher","DOI":"10.1016\/0024-3205(87)90623-0"},{"key":"e_1_2_6_36_1","doi-asserted-by":"publisher","DOI":"10.1002\/j.1875-9114.1993.tb02745.x"},{"key":"e_1_2_6_37_1","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1159\/000414631","article-title":"Opioids and pain regulation","volume":"9","author":"Lewis J","year":"1987","journal-title":"Pain Headache"},{"key":"e_1_2_6_38_1","first-page":"85","volume-title":"Orofacial pain and temporomandibular disorders","author":"Maixner W","year":"1995"},{"key":"e_1_2_6_39_1","doi-asserted-by":"publisher","DOI":"10.1213\/00000539-200302000-00034"},{"key":"e_1_2_6_40_1","first-page":"643","article-title":"A new version of the ischemic tourniquet pain test","volume":"13","author":"Maurset A","year":"1992","journal-title":"Meth Find Exp Clin Pharmacol"},{"key":"e_1_2_6_41_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-8986.1992.tb02047.x"},{"key":"e_1_2_6_42_1","doi-asserted-by":"publisher","DOI":"10.1037\/0022-006X.64.3.593"},{"key":"e_1_2_6_43_1","doi-asserted-by":"publisher","DOI":"10.1016\/0304-3959(87)91074-8"},{"key":"e_1_2_6_44_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0301-0082(02)00009-6"},{"key":"e_1_2_6_45_1","doi-asserted-by":"publisher","DOI":"10.1213\/00000539-199509000-00030"},{"key":"e_1_2_6_46_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuroscience.2007.03.029"},{"key":"e_1_2_6_47_1","doi-asserted-by":"publisher","DOI":"10.1016\/0163-8343(83)90106-8"},{"key":"e_1_2_6_48_1","doi-asserted-by":"publisher","DOI":"10.3171\/jns.1988.68.4.0621"},{"key":"e_1_2_6_49_1","doi-asserted-by":"publisher","DOI":"10.1208\/aapsj070360"},{"key":"e_1_2_6_50_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.psyneuen.2005.11.003"},{"key":"e_1_2_6_51_1","doi-asserted-by":"publisher","DOI":"10.1016\/0735-1097(95)00045-6"},{"key":"e_1_2_6_52_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1749-6632.1999.tb08663.x"},{"key":"e_1_2_6_53_1","first-page":"99","article-title":"Beta\u2010endorphin concentrations both in plasma and in cerebrospinal fluid in response to acute painful stimuli","volume":"34","author":"Spaziante R","year":"1990","journal-title":"J Neurosurg Sci"},{"key":"e_1_2_6_54_1","doi-asserted-by":"publisher","DOI":"10.1037\/013734"},{"key":"e_1_2_6_55_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.pain.2006.01.003"},{"key":"e_1_2_6_56_1","doi-asserted-by":"publisher","DOI":"10.1097\/ALN.0b013e318210f880"},{"key":"e_1_2_6_57_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0005289"},{"key":"e_1_2_6_58_1","doi-asserted-by":"publisher","DOI":"10.1037\/0022-3514.54.6.1063"},{"key":"e_1_2_6_59_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.biopsycho.2010.01.016"},{"key":"e_1_2_6_60_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.1060952"}],"container-title":["European Journal of Pain"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fj.1532-2149.2011.00021.x","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/j.1532-2149.2011.00021.x","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,9,23]],"date-time":"2023-09-23T17:09:01Z","timestamp":1695488941000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/j.1532-2149.2011.00021.x"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2011,12,19]]},"references-count":59,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2012,3]]}},"alternative-id":["10.1002\/j.1532-2149.2011.00021.x"],"URL":"https:\/\/doi.org\/10.1002\/j.1532-2149.2011.00021.x","archive":["Portico"],"relation":{},"ISSN":["1090-3801","1532-2149"],"issn-type":[{"value":"1090-3801","type":"print"},{"value":"1532-2149","type":"electronic"}],"subject":[],"published":{"date-parts":[[2011,12,19]]}}}