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Wiederhold Foundation"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,1,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>White rhinoceros are a sentinel species for important ecosystems in southern Africa. Their conservation requires active management of their population, which, in turn, requires immobilization of individuals with an ultra-potent opioid such as etorphine. Unfortunately, when immobilized with etorphine, they develop severe hypoxaemia that may contribute to morbidity and mortality. We hypothesized that (i) etorphine causes sympathetic upregulation that is responsible for physiological complications that produce hypoxaemia and (ii) butorphanol, a partial \u03bc opioid agonist, mitigates sympathetic upregulation, thereby improving arterial oxygen content (CaO2) and delivery (DO2). Six subadult male white rhinoceros were administered two treatments in random order: etorphine-saline (ES) and etorphine-butorphanol (EB). After intramuscular etorphine (~2.6 \u03bcg kg\u22121), rhinoceros became recumbent (time 0 min [t0]) and were instrumented. Baseline data were collected at t30, butorphanol (0.026 mg\/kg) or 0.9% saline was administered intravenously at t37, and data were collected again at t40 and t50. At baseline, plasma noradrenaline concentration was &amp;gt;40 ng ml\u22121, approximately twice that of non-immobilized rhinoceros (t test, P\u2009&amp;lt;\u20090.05); cardiac output (Qt, by thermodilution) and metabolic rate (VO2, by spirometry\/indirect calorimetry) were greater than predicted allometrically (t test, P\u2009&amp;lt;\u20090.05), and pulmonary hypertension was present. After butorphanol, noradrenaline concentration remained greater than in non-immobilized rhinoceros; in EB, CaO2 was greater, while Qt, DO2, VO2, and pulmonary pressures were less than in ES (linear mixed effect model, all P\u2009&amp;lt;\u20090.05). Increased noradrenaline concentration with increased Qt and hypermetabolism supports etorphine-induced sympathetic upregulation. Butorphanol partly attenuated these effects, increasing CaO2 but reducing Qt and, thus, DO2. Since plasma noradrenaline concentration remained increased after butorphanol administration while Qt, DO2, and VO2 decreased, a pathway independent of plasma noradrenaline concentration might contribute to the cardiopulmonary and hypermetabolic effects of etorphine. Developing treatments to combat this sympathomimesis could reduce capture-related morbidity in white rhinoceros.<\/jats:p>","DOI":"10.1093\/conphys\/coaf009","type":"journal-article","created":{"date-parts":[[2025,4,7]],"date-time":"2025-04-07T16:44:38Z","timestamp":1744044278000},"source":"Crossref","is-referenced-by-count":2,"title":["Etorphine induces pathophysiology in immobilized white rhinoceros through sympathomimesis that is attenuated by butorphanol"],"prefix":"10.1093","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2032-1202","authenticated-orcid":false,"given":"Jordyn M","family":"Boesch","sequence":"first","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine, Cornell University , 930 Campus Road, Ithaca, New York 14853 ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Robin D","family":"Gleed","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine, Cornell University , 930 Campus Road, Ithaca, New York 14853 ,","place":["USA"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter E","family":"Buss","sequence":"additional","affiliation":[{"name":"Veterinary Wildlife Services, South African National Parks, Kruger National Park , Private Bag X402, Skukuza 1350 ,","place":["South Africa"]},{"name":"Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria , Private Bag X04, Onderstepoort 0110 ,","place":["South Africa"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5416-3153","authenticated-orcid":false,"given":"Adrian S W","family":"Tordiffe","sequence":"additional","affiliation":[{"name":"Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria , Private Bag X04, Onderstepoort 0110 ,","place":["South Africa"]},{"name":"Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pathology and Veterinary Public Health Complex , Onderstepoort 0110 ,","place":["South Africa"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gareth E","family":"Zeiler","sequence":"additional","affiliation":[{"name":"Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria , OVAH-building, Onderstepoort Campus, Private Bag X04, Onderstepoort 0110 ,","place":["South Africa"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michele A","family":"Miller","sequence":"additional","affiliation":[{"name":"South African Medical Research Council (MRC) Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University , PO Box 241, Cape Town 8000 ,","place":["South 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