Investigation of cardiorespiratory effects of the selective 5‐HT4 agonist BIMU‐8 in etorphine‐immobilised goats (Capra aegagrus hircus) in a randomized, blinded and controlled trial. (19th February 2021) - Tod, Nadine
Abstract: Background: Opioid‐induced respiratory compromise remains a significant challenge in etorphine‐immobilised wildlife. Serotonergic agonists offer a potential avenue for preventing or treating opioid‐induced respiratory compromise. We therefore aimed to determine whether the selective 5‐hydroxytryptamine receptor 4 (5‐HT4) agonist, BIMU‐8, reverses opioid‐induced respiratory compromise in etorphine‐immobilised goats. Methods: Seven healthy adult goats were immobilised with etorphine, then treated with BIMU‐8 or sterile water 5 minutes later in a randomised, prospective cross‐over study. Cardiorespiratory variables were measured at 1‐minute intervals from 4 minutes before etorphine to 15 minutes after its administration. Arterial blood gas analyses were also performed before and after etorphine administration and the respective treatments. Results: Intravenous injection of BIMU‐8 attenuated etorphine‐induced respiratory compromise, as indicated by improvements, compared to baseline and between treatments, in respiratory rate ( f R ), peripheral arterial blood oxygen saturation (SpO2 ), partial pressure of arterial oxygen (PaO2 ) and the alveolar‐arterial oxygen partial pressure gradient (P(A‐a)O2 ). BIMU‐8 caused an increase in heart rate and a temporary decrease in arterial blood pressure. Mild movements and slight muscle spasm occurred but BIMU‐8 did not reverse immobilisation. Conclusion: Our results indicate that BIMU‐8 may be a potential drug candidate for the treatment, or prevention, of etorphine‐induced respiratory compromise in immobilised ungulates.