Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Dose-effect study of the serotonin agonist R-8-OH-DPAT on opioid-induced respiratory depression in blesbok (Damaliscus pygargus philipsi) and impala (Aepyceros melampus)

Pfitzer, S., Laubscher, L., Meyer, L., Warren, K.ORCID: 0000-0002-9328-2013, Vaughan-Higgins, R.ORCID: 0000-0001-7609-9818, Raath, J.P. and Laurence, M.ORCID: 0000-0003-1215-2848 (2019) Dose-effect study of the serotonin agonist R-8-OH-DPAT on opioid-induced respiratory depression in blesbok (Damaliscus pygargus philipsi) and impala (Aepyceros melampus). Veterinary Anaesthesia and Analgesia, 46 (6). pp. 796-806.

Link to Published Version: https://doi.org/10.1016/j.vaa.2019.06.006
*Subscription may be required

Abstract

Objective
This study aimed to determine whether the R-enantiomer of 8-hydroxy-2-(di-n-propylamino) tetralin (R-8-OH-DPAT) alleviates respiratory depression in antelope species immobilised with etorphine. The experiment also aimed to establish the most clinically effective dose of this serotonin 5- HT1A receptor agonist.

Animals
Six female blesbok and six female impala.

Study design
Each animal was subjected to four immobilisation treatments in a prospective four-way crossover design. One control treatment consisting of only etorphine at 0.09 mg kg-1 and three treatments consisting of etorphine at 0.09 mg kg-1 combined with 0.005, 0.02 and 0.07 mg kg-1 of R-8-OH-DPAT, respectively. Induction, quality of immobilisation and recovery were monitored in each treatment. Physiological variables including heart rate, respiratory rate, arterial blood pressure and blood gases, were measured over a time period of 35 minutes during immobilisation. A linear mixed model was used to assess the effects of treatments over the period of recumbence.

Results
R-8-OH-DPAT did not influence induction, immobilisation or recovery scores. Respiratory rate in blesbok was increased in the medium and high dosage R-8-OH-DPAT treatment group. However, this increased respiratory rate did not translate into improvements of arterial partial pressure of oxygen (PaO2) values in the blesbok.

The medium and higher dosages of R-8-OH-DPAT in impala led to an improved PaO2 as well as to decreased opioid-induced tachycardia during the first ten minutes of immobilisation.

Conclusions
and clinical relevance Previous reports indicated that the racemic mixture of 8-OH-DPAT injected intravenously had a positive effect on blood gas values in etorphine-treated hypoxaemic goats. In this experiment, similar effects could be seen in impala at the higher dosage rates of R-8-OH-DPAT. However, failure to achieve an improvement of blood gas values in blesbok was an unexpected result. It could be speculated that the dosage, species-specific differences of serotonin receptors or the use of the R-enantiomer of 8-OH-DPAT might play a role.

Item Type: Journal Article
Murdoch Affiliation: School of Veterinary and Life Sciences
Publisher: Elsevier Ltd.
Copyright: © 2019 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia
URI: http://researchrepository.murdoch.edu.au/id/eprint/49302
Item Control Page Item Control Page