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 opioidinduced 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 (ƒR), 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
