Skip to main content Skip to navigation

Project coordinationDr. Gabrielle Stalder Project staffDr. Friederike Pohlin

Respiratory depression induced by highly potent opioids such as etorphine remains a major challenge in wildlife anesthesia. While etorphine provides rapid and reliable immobilization, the associated respiratory depression leads to hypoxemia, hypercapnia, and acidosis. Etorphine is thought to cause respiratory impairment via activation of mu-receptors in the brainstem and induces a sympathetic stress response leading to pulmonary hypertension, among others.

Serotonin agonists, and in particular 5-HT4 receptor agonists, reduce centrally mediated opioid-induced respiratory depression because 5-HT4 receptors are co-expressed with mu-opioid receptors on brainstem respiratory neurons but have opposite effects. The 5-HT4 receptor agonist BIMU-8 has shown promise in early studies to alleviate opioid-induced respiratory depression without compromising sedation or analgesia. It is also believed that peripherally acting alpha-2 adrenoceptor antagonists may reduce some of the adverse effects of an etorphine-induced sympathetic response, particularly pulmonary hypertension.

In this study, we investigate whether BIMU-8 and the peripherally acting alpha-2 antagonist vatinoxan can attenuate or reverse etorphine-induced respiratory depression without compromising sedation or leading to additional undesirable side effects.


15 April 22-14 April 27


The Scholarship in Commemoration of Her Royal Heighness Princess Chulabhorn´s 60th Birthday Anniversary


Further staff at FIWI: Rattanathanya Hathaipat and Dr. Johanna Painer-Gigler

Further participating institutions at Vetmeduni

University Clinic for small animals, Clinical unit for anesthesiology and perioperative intensive medicine

(Further) Project partners

Prof. Leith Meyer, University of Pretoria, Pretoria, South Africa

Priv.-Doz. Dipl.-Ing. Dr. Stefan Böhmdorfer,University of Natural Resources and Life Sciences, Vienna (BOKU), Austria 

Marja  Raekallio DVM, PhD, University of Helsinki, Finland

Sponsored by the  Chulabhorn Royal Academy, Bangkok, Thailand