{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T13:31:52Z","timestamp":1790861512880,"version":"4.1.0"},"reference-count":24,"publisher":"American Physiological Society","issue":"5","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Applied Physiology"],"published-print":{"date-parts":[[2002,11,1]]},"abstract":"<jats:p> There are conflicting reports for the role of endogenous opioids on sympathetic and cardiovascular responses to exercise in humans. A number of studies have utilized naloxone (an opioid-receptor antagonist) to investigate the effect of opioids during exercise. In the present study, we examined the effect of morphine (an opioid-receptor agonist) on sympathetic and cardiovascular responses at rest and during isometric handgrip (IHG). Eleven subjects performed 2 min of IHG (30% maximum) followed by 2 min of postexercise muscle ischemia (PEMI) before and after systemic infusion of morphine (0.075 mg\/kg loading dose + 1 mg\/h maintenance) or placebo (saline) in double-blinded experiments on separate days. Morphine increased resting muscle sympathetic nerve activity (MSNA; 17 \u00b1 2 to 22 \u00b1 2 bursts\/min; P &lt; 0.01) and increased mean arterial pressure (MAP; 87 \u00b1 2 to 91 \u00b1 2 mmHg; P &lt; 0.02), but it decreased heart rate (HR; 61 \u00b1 4 to 59 \u00b1 3; P &lt; 0.01). However, IHG elicited similar increases for MSNA, MAP, and HR between the control and morphine trial (drug \u00d7 exercise interaction = not significant). Moreover, responses to PEMI were not different. Placebo had no effect on resting, IHG, and PEMI responses. We conclude that morphine modulates cardiovascular and sympathetic responses at rest but not during isometric exercise. <\/jats:p>","DOI":"10.1152\/japplphysiol.00462.2002","type":"journal-article","created":{"date-parts":[[2015,3,3]],"date-time":"2015-03-03T15:42:35Z","timestamp":1425397355000},"page":"1764-1769","source":"Crossref","is-referenced-by-count":15,"title":["Effect of morphine on sympathetic nerve activity  in humans"],"prefix":"10.1152","volume":"93","author":[{"given":"Jason R.","family":"Carter","sequence":"first","affiliation":[{"name":"Division of Cardiology, Department of Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Charity L.","family":"Sauder","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Department of Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chester A.","family":"Ray","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Department of Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033; and"},{"name":"Cardiovascular Center and Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, Iowa 52242"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"24","reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1097\/00000542-197505000-00006"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.2000.279.5.R1565"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1038\/clpt.1983.83"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1152\/ajpendo.1991.260.3.E379"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1016\/0306-4522(86)90262-9"},{"key":"B8","first-page":"409","volume":"14","author":"Floras JS.","year":"1991","journal-title":"Clin Invest Med"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1992.73.5.2028"},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1990.68.6.2466"},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.1213\/00000539-198106000-00007"},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.1016\/0033-0620(85)90004-0"},{"key":"B13","doi-asserted-by":"publisher","DOI":"10.1111\/j.1399-6576.1993.tb03598.x"},{"key":"B14","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM196912182812503"},{"key":"B15","doi-asserted-by":"publisher","DOI":"10.1161\/01.RES.57.3.461"},{"key":"B16","doi-asserted-by":"publisher","DOI":"10.1213\/00000539-200007000-00010"},{"key":"B17","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.ph.45.030183.001305"},{"key":"B18","doi-asserted-by":"publisher","DOI":"10.1097\/00000542-199806000-00020"},{"key":"B19","doi-asserted-by":"publisher","DOI":"10.1097\/00000542-198109000-00019"},{"key":"B20","doi-asserted-by":"publisher","DOI":"10.1016\/0006-8993(86)90095-8"},{"key":"B21","doi-asserted-by":"publisher","DOI":"10.1097\/00005344-198609000-00011"},{"key":"B22","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1993.75.1.228"},{"key":"B23","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1994.77.1.231"},{"key":"B24","doi-asserted-by":"publisher","DOI":"10.1172\/JCI114916"},{"key":"B25","doi-asserted-by":"publisher","DOI":"10.1161\/01.CIR.72.5.982"},{"key":"B26","doi-asserted-by":"publisher","DOI":"10.1378\/chest.68.2.222"}],"container-title":["Journal of Applied Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.physiology.org\/doi\/pdf\/10.1152\/japplphysiol.00462.2002","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,9,8]],"date-time":"2019-09-08T16:19:09Z","timestamp":1567959549000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.physiology.org\/doi\/10.1152\/japplphysiol.00462.2002"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2002,11,1]]},"references-count":24,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2002,11,1]]}},"alternative-id":["10.1152\/japplphysiol.00462.2002"],"URL":"https:\/\/doi.org\/10.1152\/japplphysiol.00462.2002","relation":{},"ISSN":["8750-7587","1522-1601"],"issn-type":[{"value":"8750-7587","type":"print"},{"value":"1522-1601","type":"electronic"}],"subject":[],"published":{"date-parts":[[2002,11,1]]}}}