Aarhus University Seal / Aarhus Universitets segl

Catherine Williams

Tachycardia in response to remote capsaicin injection as a model for nociception in the ball python (Python regius)

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskningpeer review


  • Catherine J A Williams
  • Lauren E James, Section for Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark.
  • ,
  • Mads F Bertelsen, Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Copenhagen, Denmark.
  • ,
  • Tobias Wang

OBJECTIVES: To quantify the effect of subcutaneous (SC) capsaicin injection on heart rate (HR) in ball pythons (Python regius) and to assess the efficacy of two opioids (morphine and butorphanol) in modifying this response.

STUDY DESIGN: Prospective, randomized, unmatched study.

ANIMALS: Eleven mixed-sex, captive-bred ball pythons.

METHODS: Snakes were randomly assigned to three groups (n = 6) by intramuscular premedication: 1) control: saline (0.9 mL); 2) morphine (10 mg kg(-1) ); and 3) butorphanol (10 mg kg(-1) ). Three snakes were tested twice and another two were tested three times in different treatments administered 1 month apart. Under isoflurane anaesthesia, snakes were instrumented with SC electrocardiogram (ECG) electrodes and an SC catheter for remote stimulus delivery. After recovery from anaesthesia, all snakes, in visual and audial isolation from the experimenter, received a sham stimulus of saline (0.4 mL) via the SC catheter. A nociceptive stimulus of SC capsaicin (3 mg in 0.2 mL saline with 7% Tween 80) was then applied by catheter at 7 hours after premedication. In a subset (n = 3), two sham injections (saline 0.2 mL) preceded the capsaicin treatment. HR was recorded via ECG, and changes in HR (ΔHR) from baseline were calculated for all stimulations.

RESULTS: Capsaicin injection was associated with a significant increase in HR [peak ΔHR: saline group: 8.8 ± 7.1 beats minute(-1) ; capsaicin group: 21.1 ± 5.8 beats minute(-1) (p = 0.0055)] and integrated ΔHR as a function of time. The administration of morphine or butorphanol 7 hours prior to nociception failed to significantly reduce the peak and integrated ΔHR. Butorphanol caused marked, long-lasting sedation as assessed by muscle tone.

CONCLUSIONS AND CLINICAL RELEVANCE: The HR response to an SC capsaicin injection can serve as a nociceptive model in P. regius. Morphine and butorphanol administration did not reduce HR response to capsaicin stimulation but produced significantly different effects on pre-stimulation HR and sedation.

TidsskriftVeterinary Anaesthesia and Analgesia
Sider (fra-til)429-34
Antal sider6
StatusUdgivet - jul. 2016

Se relationer på Aarhus Universitet Citationsformater

ID: 108511639