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Leith C. R. Meyer - One of the best experts on this subject based on the ideXlab platform.

  • muscle tremors observed in white rhinoceroses immobilised with either Etorphine azaperone or Etorphine midazolam an initial study
    Journal of The South African Veterinary Association-tydskrif Van Die Suid-afrikaanse Veterinere Vereniging, 2021
    Co-Authors: Mary Nasr, Leith C. R. Meyer, Peter Buss, Jordyn M. Boesch, Robin D. Gleed, Maria C Fabregas, Friederike Pohlin
    Abstract:

    Etorphine–azaperone is the most commonly used drug combination for chemical immobilisation of free-ranging white rhinoceroses, but causes several profound physiological disturbances, including muscle tremors. The addition of benzodiazepine sedatives, such as midazolam, has been proposed to reduce the muscular rigidity and tremors in immobilised rhinoceroses. Twenty-three free-ranging, sub-adult white rhinoceros bulls were darted and captured using a combination of Etorphine plus either azaperone or midazolam. Skeletal muscle tremors were visually evaluated and scored by an experienced veterinarian, and tremor scores and distance run were compared between groups using the Wilcoxon rank sum test. No statistical differences were observed in tremor scores ( p = 0.435) or distance run ( p = 0.711) between the two groups, and no correlation between these variables was detected ( r = –0.628; p = 0.807). Etorphine–midazolam was as effective as Etorphine–azaperone at immobilising rhinoceroses, with animals running similar distances. Although the addition of midazolam to the Etorphine did not reduce tremor scores compared to azaperone, it might have other beneficial immobilising effects in rhinoceroses, and further investigation is necessary to elucidate possible methods of reducing muscle tremoring during chemical immobilisation of rhinoceroses.

  • 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
    Veterinary Record, 2021
    Co-Authors: Nadine Tod, Anna Haw, Gabrielle Stalder, Hanna Rauch, Stefan Boehmdorfer, Hanno Gerritsmann, Johanna Painer, Leith C. R. Meyer
    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 (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.

  • comparison of cardiopulmonary effects of Etorphine and thiafentanil administered as sole agents for immobilization of impala aepyceros melampus
    Veterinary Anaesthesia and Analgesia, 2021
    Co-Authors: Silke Pfitzer, Leith C. R. Meyer, Liesel L. Laubscher, Jacobus P. Raath, K Warren, Rebecca Vaughanhiggins, M Laurence
    Abstract:

    Abstract Objective To compare the cardiopulmonary effects of the opioids Etorphine and thiafentanil for immobilization of impala. Study design Two-way crossover, randomized study. Animals A group of eight adult female impala. Methods Impala were given two treatments: 0.09 mg kg–1 Etorphine or 0.09 mg kg–1 thiafentanil via remote dart injection. Time to recumbency, quality of immobilization and recovery were assessed. Respiratory rate, heart rate (HR), mean arterial blood pressure (MAP) and arterial blood gases were measured. A linear mixed model was used to analyse the effects of treatments, treatments over time and interactions of treatment and time (p Results Time to recumbency was significantly faster with thiafentanil (2.0 ± 0.8 minutes) than with Etorphine (3.9 ± 1.6 minutes; p = 0.007). Both treatments produced bradypnoea, which was more severe at 5 minutes with thiafentanil (7 ± 4 breaths minute–1) than with Etorphine (13 ± 12 breaths minute–1; p = 0.004). HR increased with both treatments but significantly decreased over time when Etorphine (132 ± 17 to 82 ± 11 beats minute–1) was compared with thiafentanil (113 ± 22 to 107 ± 36 beats minute–1; p Conclusions and clinical relevance The shorter time to recumbency with thiafentanil may allow easier and faster retrieval in the field. However, thiafentanil caused greater hypertension, and ventilatory effects during the first 10 minutes, after administration.

  • comparison of some cardiopulmonary effects of Etorphine and thiafentanil during the chemical immobilization of blesbok damaliscus pygargus phillipsi
    Veterinary Anaesthesia and Analgesia, 2021
    Co-Authors: Silke Pfitzer, Leith C. R. Meyer, Liesel L. Laubscher, Jacobus P. Raath, K Warren, Rebecca Vaughanhiggins, M Laurence
    Abstract:

    Abstract Objective To determine the cardiopulmonary effects of Etorphine and thiafentanil for immobilization of blesbok. Study design Blinded, randomized, two-way crossover study. Animals A group of eight adult female blesbok. Methods Animals were immobilized twice, once with Etorphine (0.09 mg kg–1) and once with thiafentanil (0.09 mg kg–1) administered intramuscularly by dart. Immobilization quality was assessed and analysed by Wilcoxon signed-rank test. Time to final recumbency was compared between treatments by one-way analysis of variance. Cardiopulmonary effects including respiratory rate (ƒR), arterial blood pressures and arterial blood gases were measured. A linear mixed model was used to assess the effects of drug treatments over the 40 minute immobilization period. Significant differences between treatments, for treatment over time as well as effect of treatment by time on the variables, were analysed (p Results There was no statistical difference (p = 0.186) between treatments for time to recumbency. The mean ƒR was lower with Etorphine (14 breaths minute–1) than with thiafentanil (19 breaths minute–1, p = 0.034). The overall mean PaCO2 was higher with Etorphine [45 mmHg (6.0 kPa)] than with thiafentanil [41 mmHg (5.5 kPa), p = 0.025], whereas PaO2 was lower with Etorphine [53 mmHg (7.1 kPa)] than with thiafentanil [64 mmHg (8.5 kPa), p Conclusions Both drugs caused clinically relevant hypoxaemia; however, it was less severe with thiafentanil. Ventilation was adequate. Hypertension was greater and immobilization scores were lower with thiafentanil.

  • what hinders pulmonary gas exchange and changes distribution of ventilation in immobilized white rhinoceroses ceratotherium simum in lateral recumbency
    Journal of Applied Physiology, 2020
    Co-Authors: Martina Mosing, Gareth E. Zeiler, Peter Buss, Michele A Miller, Jordyn M. Boesch, Robin D. Gleed, Andreas D Waldmann, Muriel Sacks, Giselle Hosgood, Leith C. R. Meyer
    Abstract:

    Electrical impedance tomography measurements of regional ventilation and perfusion applied to Etorphine-immobilized white rhinoceroses in lateral recumbency revealed a pronounced disproportional sh...

Leeyuan Liuchen - One of the best experts on this subject based on the ideXlab platform.

  • differential regulation of the human κ opioid receptor by agonists Etorphine and levorphanol reduced dynorphin a and u50 488h induced internalization and phosphorylation
    Journal of Pharmacology and Experimental Therapeutics, 2003
    Co-Authors: Jianguo Li, Fengqin Zhang, Leeyuan Liuchen
    Abstract:

    We previously observed that ( trans )-3,4-dichloro- N -methyl- N -[2-(1-pyrrolidinyl)-cyclohexyl]benzeneacetamide (U50,488H) promoted internalization and phosphorylation of the FLAG-tagged human κ opioid receptor (FLAG-hkor) stably expressed in Chinese hamster ovary (CHO) cells. In this study, we compared regulation of the FLAG-hkor expressed in CHO cells by U50,488H, dynorphin A, Etorphine, and levorphanol, which were potent full agonists as determined by stimulation of guanosine 5′- O -(3-[ 35 S]thio)triphosphate binding. Using fluorescence flow cytometry, we found that dynorphin A(1-17), like U50,488H, promoted internalization of the FLAG-hkor in a time- and dose-dependent manner. The antagonists naloxone and norbinaltorphimine, having no effect on FLAG-hkor internalization, effectively blocked dynorphin A(1-17)- and U50,488H-induced internalization. Interestingly, the full agonists Etorphine and levorphanol did not cause internalization of the FLAG-hkor but significantly reduced dynorphin A(1-17)- and U50,488H-induced internalization in a dose-dependent manner. Immunofluorescence staining of FLAG-hkor yielded similar results. Dynorphin A(1-17) and U50,488H enhanced phosphorylation of FLAG-hkor to a greater extent than Etorphine, but levorphanol did not increase FLAG-hkor phosphorylation. Etorphine or levorphanol decreased dynorphin- or U50,488H-induced phosphorylation. It is likely that conformations of the hkor required for phosphorylation and initiation of internalization are different from those for activation of G proteins. We also examined whether the four agonists had differential effects on superactivation of adenylate cyclase. Pretreatment with U50,488H, dynorphin A(1-17), or Etorphine enhanced forskolin-stimulated adenylate cyclase activity to ∼200 to 250% of the control, whereas levorphanol pretreatment did not result in significant adenylate cyclase superactivation. Thus, the degree of superactivation caused by an agonist is unrelated to its ability to promote internalization of the hkor.

  • differential regulation of the human κ opioid receptor by agonists Etorphine and levorphanol reduced dynorphin a and u50 488h induced internalization and phosphorylation
    Journal of Pharmacology and Experimental Therapeutics, 2003
    Co-Authors: Fengqin Zhang, Xilu Jin, Leeyuan Liuchen
    Abstract:

    We previously observed that (trans)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]benzeneacetamide (U50,488H) promoted internalization and phosphorylation of the FLAG-tagged human kappa opioid receptor (FLAG-hkor) stably expressed in Chinese hamster ovary (CHO) cells. In this study, we compared regulation of the FLAG-hkor expressed in CHO cells by U50,488H, dynorphin A, Etorphine, and levorphanol, which were potent full agonists as determined by stimulation of guanosine 5'-O-(3-[(35)S]thio)triphosphate binding. Using fluorescence flow cytometry, we found that dynorphin A(1-17), like U50,488H, promoted internalization of the FLAG-hkor in a time- and dose-dependent manner. The antagonists naloxone and norbinaltorphimine, having no effect on FLAG-hkor internalization, effectively blocked dynorphin A(1-17)- and U50,488H-induced internalization. Interestingly, the full agonists Etorphine and levorphanol did not cause internalization of the FLAG-hkor but significantly reduced dynorphin A(1-17)- and U50,488H-induced internalization in a dose-dependent manner. Immunofluorescence staining of FLAG-hkor yielded similar results. Dynorphin A(1-17) and U50,488H enhanced phosphorylation of FLAG-hkor to a greater extent than Etorphine, but levorphanol did not increase FLAG-hkor phosphorylation. Etorphine or levorphanol decreased dynorphin- or U50,488H-induced phosphorylation. It is likely that conformations of the hkor required for phosphorylation and initiation of internalization are different from those for activation of G proteins. We also examined whether the four agonists had differential effects on superactivation of adenylate cyclase. Pretreatment with U50,488H, dynorphin A(1-17), or Etorphine enhanced forskolin-stimulated adenylate cyclase activity to approximately 200 to 250% of the control, whereas levorphanol pretreatment did not result in significant adenylate cyclase superactivation. Thus, the degree of superactivation caused by an agonist is unrelated to its ability to promote internalization of the hkor.

Fengqin Zhang - One of the best experts on this subject based on the ideXlab platform.

  • differential regulation of the human κ opioid receptor by agonists Etorphine and levorphanol reduced dynorphin a and u50 488h induced internalization and phosphorylation
    Journal of Pharmacology and Experimental Therapeutics, 2003
    Co-Authors: Jianguo Li, Fengqin Zhang, Leeyuan Liuchen
    Abstract:

    We previously observed that ( trans )-3,4-dichloro- N -methyl- N -[2-(1-pyrrolidinyl)-cyclohexyl]benzeneacetamide (U50,488H) promoted internalization and phosphorylation of the FLAG-tagged human κ opioid receptor (FLAG-hkor) stably expressed in Chinese hamster ovary (CHO) cells. In this study, we compared regulation of the FLAG-hkor expressed in CHO cells by U50,488H, dynorphin A, Etorphine, and levorphanol, which were potent full agonists as determined by stimulation of guanosine 5′- O -(3-[ 35 S]thio)triphosphate binding. Using fluorescence flow cytometry, we found that dynorphin A(1-17), like U50,488H, promoted internalization of the FLAG-hkor in a time- and dose-dependent manner. The antagonists naloxone and norbinaltorphimine, having no effect on FLAG-hkor internalization, effectively blocked dynorphin A(1-17)- and U50,488H-induced internalization. Interestingly, the full agonists Etorphine and levorphanol did not cause internalization of the FLAG-hkor but significantly reduced dynorphin A(1-17)- and U50,488H-induced internalization in a dose-dependent manner. Immunofluorescence staining of FLAG-hkor yielded similar results. Dynorphin A(1-17) and U50,488H enhanced phosphorylation of FLAG-hkor to a greater extent than Etorphine, but levorphanol did not increase FLAG-hkor phosphorylation. Etorphine or levorphanol decreased dynorphin- or U50,488H-induced phosphorylation. It is likely that conformations of the hkor required for phosphorylation and initiation of internalization are different from those for activation of G proteins. We also examined whether the four agonists had differential effects on superactivation of adenylate cyclase. Pretreatment with U50,488H, dynorphin A(1-17), or Etorphine enhanced forskolin-stimulated adenylate cyclase activity to ∼200 to 250% of the control, whereas levorphanol pretreatment did not result in significant adenylate cyclase superactivation. Thus, the degree of superactivation caused by an agonist is unrelated to its ability to promote internalization of the hkor.

  • differential regulation of the human κ opioid receptor by agonists Etorphine and levorphanol reduced dynorphin a and u50 488h induced internalization and phosphorylation
    Journal of Pharmacology and Experimental Therapeutics, 2003
    Co-Authors: Fengqin Zhang, Xilu Jin, Leeyuan Liuchen
    Abstract:

    We previously observed that (trans)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]benzeneacetamide (U50,488H) promoted internalization and phosphorylation of the FLAG-tagged human kappa opioid receptor (FLAG-hkor) stably expressed in Chinese hamster ovary (CHO) cells. In this study, we compared regulation of the FLAG-hkor expressed in CHO cells by U50,488H, dynorphin A, Etorphine, and levorphanol, which were potent full agonists as determined by stimulation of guanosine 5'-O-(3-[(35)S]thio)triphosphate binding. Using fluorescence flow cytometry, we found that dynorphin A(1-17), like U50,488H, promoted internalization of the FLAG-hkor in a time- and dose-dependent manner. The antagonists naloxone and norbinaltorphimine, having no effect on FLAG-hkor internalization, effectively blocked dynorphin A(1-17)- and U50,488H-induced internalization. Interestingly, the full agonists Etorphine and levorphanol did not cause internalization of the FLAG-hkor but significantly reduced dynorphin A(1-17)- and U50,488H-induced internalization in a dose-dependent manner. Immunofluorescence staining of FLAG-hkor yielded similar results. Dynorphin A(1-17) and U50,488H enhanced phosphorylation of FLAG-hkor to a greater extent than Etorphine, but levorphanol did not increase FLAG-hkor phosphorylation. Etorphine or levorphanol decreased dynorphin- or U50,488H-induced phosphorylation. It is likely that conformations of the hkor required for phosphorylation and initiation of internalization are different from those for activation of G proteins. We also examined whether the four agonists had differential effects on superactivation of adenylate cyclase. Pretreatment with U50,488H, dynorphin A(1-17), or Etorphine enhanced forskolin-stimulated adenylate cyclase activity to approximately 200 to 250% of the control, whereas levorphanol pretreatment did not result in significant adenylate cyclase superactivation. Thus, the degree of superactivation caused by an agonist is unrelated to its ability to promote internalization of the hkor.

Peter Buss - One of the best experts on this subject based on the ideXlab platform.

  • muscle tremors observed in white rhinoceroses immobilised with either Etorphine azaperone or Etorphine midazolam an initial study
    Journal of The South African Veterinary Association-tydskrif Van Die Suid-afrikaanse Veterinere Vereniging, 2021
    Co-Authors: Mary Nasr, Leith C. R. Meyer, Peter Buss, Jordyn M. Boesch, Robin D. Gleed, Maria C Fabregas, Friederike Pohlin
    Abstract:

    Etorphine–azaperone is the most commonly used drug combination for chemical immobilisation of free-ranging white rhinoceroses, but causes several profound physiological disturbances, including muscle tremors. The addition of benzodiazepine sedatives, such as midazolam, has been proposed to reduce the muscular rigidity and tremors in immobilised rhinoceroses. Twenty-three free-ranging, sub-adult white rhinoceros bulls were darted and captured using a combination of Etorphine plus either azaperone or midazolam. Skeletal muscle tremors were visually evaluated and scored by an experienced veterinarian, and tremor scores and distance run were compared between groups using the Wilcoxon rank sum test. No statistical differences were observed in tremor scores ( p = 0.435) or distance run ( p = 0.711) between the two groups, and no correlation between these variables was detected ( r = –0.628; p = 0.807). Etorphine–midazolam was as effective as Etorphine–azaperone at immobilising rhinoceroses, with animals running similar distances. Although the addition of midazolam to the Etorphine did not reduce tremor scores compared to azaperone, it might have other beneficial immobilising effects in rhinoceroses, and further investigation is necessary to elucidate possible methods of reducing muscle tremoring during chemical immobilisation of rhinoceroses.

  • what hinders pulmonary gas exchange and changes distribution of ventilation in immobilized white rhinoceroses ceratotherium simum in lateral recumbency
    Journal of Applied Physiology, 2020
    Co-Authors: Martina Mosing, Gareth E. Zeiler, Peter Buss, Michele A Miller, Jordyn M. Boesch, Robin D. Gleed, Andreas D Waldmann, Muriel Sacks, Giselle Hosgood, Leith C. R. Meyer
    Abstract:

    Electrical impedance tomography measurements of regional ventilation and perfusion applied to Etorphine-immobilized white rhinoceroses in lateral recumbency revealed a pronounced disproportional sh...

  • Etorphine ketamine constant rate infusion for maintenance of anaesthesia in a compromised white rhinoceros ceratotherium simum
    Case reports in Veterinary Medicine, 2019
    Co-Authors: Friederike Pohlin, Peter Buss, Michele A Miller, Jordyn M. Boesch, Robin D. Gleed, Gerhard Steenkamp, Luke Alexander Poore, Gareth E. Zeiler
    Abstract:

    A subadult white rhinoceros bull presented for oesophageal endoscopic evaluation and foreign body removal under general anaesthesia. The animal had a history of nasal and oral regurgitation of water and ingesta with weight-loss for 6 days prior to the procedure and had been diagnosed with oesophageal obstruction caused by a bailing wire. Anaesthesia was induced with intramuscular Etorphine and azaperone delivered remotely by dart, followed by an intravenous bolus of ketamine. The trachea was intubated, and anaesthesia was maintained with an Etorphine-ketamine constant rate infusion (CRI). The rhinoceros did not respond predictably to induction of anaesthesia and developed life-threatening systemic hypotension throughout the 90-minute procedure. A mega-vertebrate demand ventilator was successfully used to provide intermittent positive pressure ventilation when the rhinoceros developed apnoea. This case report describes the maintenance of anaesthesia of a white rhinoceros using an Etorphine-ketamine CRI and the causes and management of hypotension and respiratory impairment observed in this patient.

  • Effects of a supplemental Etorphine dose on pulmonary artery pressure and cardiac output in immobilized, boma-habituated white rhinoceros (Ceratotherium simum): a preliminary study.
    Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians, 2018
    Co-Authors: Jordyn M. Boesch, Gareth E. Zeiler, Markus Hofmeyr, Peter Buss, Robin D. Gleed, Adrian S. W. Tordiffe, Leith C. R. Meyer
    Abstract:

    Abstract The effects of Etorphine on the pulmonary vascular system of white rhinoceros (Ceratotherium simum) have not been described and could play a role in the severe hypoxemia that develops after immobilization with Etorphine-based drug combinations. Characterization of these effects requires measurement of pulmonary vascular pressures and cardiac output (CO). To refine a technique for pulmonary arterial catheterization, five boma-habituated white rhinoceros (three females and two males weighing 1,012–1,572 kg) were immobilized by remote injection with Etorphine plus azaperone followed by butorphanol. This afforded the opportunity to perform a pilot study and acquire preliminary measurements of pulmonary arterial pressure (PAP) and CO before and after supplemental Etorphine given intravenously. Ultrasonographic guidance was used to insert a sheath introducer into a linguofacial branch of a jugular vein. A 160-cm-long pulmonary artery catheter with a balloon and thermistor was then passed through the in...

  • Use of butorphanol and diprenorphine to counter respiratory impairment in the immobilised white rhinoceros (Ceratotherium simum).
    Journal of the South African Veterinary Association, 2018
    Co-Authors: Leith C. R. Meyer, Andrea Fuller, Markus Hofmeyr, Peter Buss, Michele Miller, Anna Haw
    Abstract:

    Opioid-induced immobilisation results in severe respiratory impairment in the white rhinoceros. It has therefore been attempted in the field to reverse this impairment with the use of opioid agonist-antagonists, such as nalorphine, nalbuphine, butorphanol and diprenorphine; however, the efficacy of some of these treatments has yet to be determined. The efficacy of butorphanol, either alone or in combination with diprenorphine both with and without oxygen insufflation, in alleviating opioid-induced respiratory impairment was evaluated. The study was performed in two parts: a boma trial and a field trial. Rhinoceroses were immobilised specifically for the study, according to a strict protocol to minimise confounding variables. A two-way analysis of variance was used to compare the physiological responses of the rhinoceroses to the different treatments and their effects over time. The intravenous administration of butorphanol (at 3.3 mg per mg Etorphine) plus diprenorphine (at 0.4 mg per mg Etorphine) did not offer any advantage over butorphanol (at 15 mg per mg Etorphine) alone with regard to improving PaO2, PaCO2 and respiratory rates in Etorphine-immobilised white rhinoceroses. Both butorphanol + diprenorphine + oxygen and butorphanol + oxygen, at the doses used, significantly improved the Etorphine-induced hypoxaemia in both boma- and field-immobilised white rhinoceroses. Clinically acceptable oxygenation in field-immobilised white rhinoceroses can be achieved by using either treatment regimen, provided that it is combined with oxygen insufflation.

David Griffiths - One of the best experts on this subject based on the ideXlab platform.

  • Creative Commons License
    2016
    Co-Authors: David Griffiths, Erik W. Born, Mario Acquarone
    Abstract:

    Prolonged chemical restraint of walrus (Odobenus rosmarus) with Etorphine supplemented with medetomidin

  • Prolonged chemical restraint of walrus ( Odobenus rosmarus ) with Etorphine supplemented with medetomidine
    NAMMCO Scientific Publications, 2014
    Co-Authors: David Griffiths, Erik W. Born, Mario Acquarone
    Abstract:

    Physiological studies involving the use of isotopic water required chemical restraint of free-ranging walruses ( Odobenus rosmarus ) for several hours. In August 2000, six male walrus (total body mass: 1050–1550 kg) were immobilized in East Greenland by remote delivery of 8.0–9.8 mg of Etorphine and subsequently restrained for up to 6.75 h by administration of medetomidine. The effects of Etorphine were reversed with 10–24 mg diprenorphine. After termination of the Etorphine-induced apnoea, lasting an average of 15.8 min (SD = 9.7, range = 9.5–35.2 min, n = 6), the animals were initially given 10–20 mg medetomidine intramuscularly. The initial dose was further augmented by 5 mg at intervals of 5 min. In two cases, when medetomidine was administered through a catheter inserted in the extradural vein, the animal became instantly apnoeic and regained respiratory function only after intravenous injection of the prescribed dose of the antagonist atipamezole and of the respiratory stimulant doxapram. After an average of 3.5 hours of immobilisation, rectal temperature began to increase and it is conceivable that this is the factor that will ultimately limit the duration of immobilisation. The animals became conscious and fully mobile shortly after an intravenous injection of a dose of atipamezole approximately twice the mass of the total dose of medetomidine given during the procedure followed by 400 mg of doxapram. It is concluded that medetomidine appears to be a suitable drug for chemical restraint of walruses for time-consuming procedures following initial immobilisation by Etorphine. With animals of total body mass around 1,000–1,500 kg, the drug should be given intramuscularly in 10–20 mg increments (total mass 10–60 mg) until the breathing rate falls to approximately 1 min-1. At this level, breathing is maintained and animals do not respond to touch or injection.

  • Evaluation of Etorphine reversed by diprenorphine for the immobilisation of free-ranging Atlantic walrus ( Odobenus rosmarus rosmarus L.)
    NAMMCO Scientific Publications, 2014
    Co-Authors: Mario Acquarone, Erik W. Born, David Griffiths, Lars Øyvind Knutsen, Øystein Wiig, Ian Gjertz
    Abstract:

    To date no problem-free method exists for the immobilisation of free‑ranging walruses ( Odobenus rosmarus ). In the period 1989-2001, 69 immobilisations with Etorphine HCl were performed by remote darting of 41 individual free-ranging adult Atlantic walruses ( O. r. rosmarus ), with body masses 633 ‑ 1883 kg, as a rerequisite for the attachment of radio tracking and dive recording instruments, and for studies of metabolism. Ten individuals were immobilised several times. We present data on these 69 immobilisations and evaluate the method. Full immobilisation was achieved in 58 cases (84 %). The animals were insufficiently restrained in 6 cases (9 %) and 5 animals died (7 %) following the immobilisation. The animals were fully immobilised and approachable after 5 min (n = 38, range = 1.9 ‑ 12.4 min, SD = 2.2) with a dose of Etorphine of 6.1 μg/kg (range 2.4 ‑ 12.6 μg /kg, SD = 2.4). Induction time was negatively correlated with the dosage of Etorphine. Etorphine-induced apnoea lasted 13.7 min (n = 36, range 17.0 ‑ 26.7 min, SD = 5.1) and was reversed by multiple doses of the antagonist diprenorphine HCl. The first dose of antagonist of 12.2 mg (n = 39, range 6.0 ‑ 21.0 mg, SD = 3.5) was administered 8.4 min (n = 38, range 4.7 ‑ 18.0 min, SD = 2.8) after injection of the agonist. The total dose of diprenorphine per animal ranged between 7.7 and 41.7 μg/kg (n = 31, mean  = 17.2 μg/kg, SD = 7.5). For some animals blood pH values were measured following the apnoea and reached low levels (min pH 6.8). For animals that were immobilised several times there were no indications of changed sensitivity to Etorphine as reflected in unchanged induction times. Mortalities could neither be related to the doses of agonist and antagonist, nor to the times of administration of the drugs. From this (n = 69) and other (n = 103) studies involving Etorphine immobilisation of walruses (both Atlantic and Pacific) the overall success rate is 83 % (8 % casualty rate). We conclude that the combination Etorphine‑ diprenorphine is suitable for both single and multiple immobilisations of walruses provided that (a) a casualty rate of 7-8% is acceptable (b) the antagonist diprenorphine is administered fast and well into a tissue with good blood irrigation, and (c) the animal is promptly intubated endotracheally to facilitate the restoration of breathing after drug-induced apnoea.

  • IMMOBILIZATION OF WALRUS WITH Etorphine HYDROCHLORIDE AND ZOLETIL
    Marine Mammal Science, 1993
    Co-Authors: David Griffiths, Øystein Wiig, Ian Gjertz
    Abstract:

    The Norwegian Polar Research Institute, Rolfstangveien 12, N-1330 Oslo Lufthavn, Norway IAN GJERTZ The Norwegian Polar Research Institute, N-9170 Longyearbyen, Norway ABSTRACT The paper describes the use of the drugs Zoletil@ and Etorphine for the immobilization of walrus (Odobenus rosmarus rosmarus) for attachment of satellite telemetry equipment. Three animals weighing approximately 1,500 kg each were injected intramuscularly with Zoletil@ at a dose between 1.4 and 2.2 mg/ kg. One walrus died while the two others were adequately restrained. The induction time was between 14 and 29 minutes and the effect lasted for 75- 220 min. Thirty-eight animals of weight 900-1,500 kg were darted intramuscularly with Etorphine at a dose between 3.3 and 8 mg/kg. Thirty-six were immobilized although one died later. The induction time for Etorphine was two to ten minutes. The action of this drug was terminated with an injection of the antidote di- prenorphine. The use of Etorphine was accompanied by convulsive movements and apnoea while Zoletil@ produced a gradual and smooth entry into and withdrawal from immobilization. Key words: walrus, Odobenus rosmarus rosmarus immobilization, Etorphine, Zo- letil @ , marine mammal, seal. Etorphine