Source: UNIVERSITY OF TENNESSEE submitted to
PAIN RELIEVING EFFECTS OF OPOIDS AND NONSTEROIDAL ANTI-INFLAMMATORY DRUGS IN BEARDED DRAGONS
Sponsoring Institution
Cooperating Schools of Veterinary Medicine
Project Status
EXTENDED
Funding Source
Reporting Frequency
Annual
Accession No.
0211795
Grant No.
(N/A)
Project No.
TENV21162GREENACREMA
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2006
Project End Date
Mar 30, 2008
Grant Year
(N/A)
Project Director
Greenacre, C. B.
Recipient Organization
UNIVERSITY OF TENNESSEE
2621 MORGAN CIR
KNOXVILLE,TN 37996-4540
Performing Department
COMPARATIVE MEDICINE
Non Technical Summary
The type and dose of analgesics needed to relieve pain in reptiles is unknown because studies, including the development of valid pain models, are lacking. Based on our preliminary studies, we developed a valid pain model for use in reptiles to compare the effects of various analgesics using minimal electrostimulation of the tail as a stimulus. We propose to evaluate various analgesics using this pain model to learn how to better alleviate pain in reptiles.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
31538301020100%
Goals / Objectives
The type and dose of analgesics needed to relieve pain in reptiles is unknown because studies, including developing valid pain models, are lacking. Based on our preliminary studies in green iguanas, we developed a valid pain model for use in reptiles to compare the effects of various analgesics using minimal electrostimulation of the tail as a stimulus. We propose to evaluate various analgesics using this pain model to learn how to better alleviate pain in reptiles. We hypothesize that analgesics such as opioids and nonsteroidal anti-inflammatory drugs (NSAIDS) provide a measurable degree of pain relief to bearded dragons. Our objective is to evaluate the pain relieving effects of various opioids and nonsteroidal anti-inflammatory medications, as compared to saline, by evaluating the response of 20 bearded dragons to near threshold and superthreshold electrostimulations of the tail. Evaluation of opioids including butorphanol, morphine and tramadol, and of NSAIDS including carprofen, ketoprofen, meloxicam and flunixin meglumine will be conducted.
Project Methods
20 adult bearded dragons (Amphibolurus barbatus) will be administered a similar volume of saline, or an opioid analgesic, or an NSAID intramuscularly 30 minutes prior to electrostimulation of the tail to compare responses. Each medication will be administered to each bearded dragon at least 3 days apart so that the previous medication has time to be eliminated from the body and each can act as their own control. Based on information from our previous study, the opioid analgesics administered will be butorphanol at 1.5, 4.0, and 8.0 mg/kg IM, morphine at 1.0 mg/kg and tramadol at 4mg/kg IV (tail vein) and 11 mg/kg PO. The nonsteroidal anti-inflammatory medications administered will be carprofen at 2 and 4 mg/kg IM, ketoprofen at 2 mg/kg IM and 4.0 mg/kg PO, meloxicam at 0.2 and 0.4 mg/kg IM and flunixin meglumine at 2 mg/kg IM. The electrostimulation will be delivered through a cutaneous electrode attached to the tail, while a Doppler probe is placed on the chest. The stimulations will be administered using a Grass stimulator with the two electrodes placed 1 cm apart on the lateral side of the tail, one third the distance from the base, at a current of 2, 10, 20, and 40 milliamps in random order for a duration of 50 milliseconds, 10 minutes apart. Based on our previous study in iguanas, the 2 milliamp electrostimulation for a duration of 500 milliseconds resulted in minimal to no response, but for the bearded dragons the same threshold response was achieved with a duration of 50 msec. The animals' response will be recorded on videotape. Three blinded evaluators will assign a score on a multiple parameter response scale developed in our previous study. The response scale assigns an objective score to increasing heart rates, and to movements of the tail, head and body. The bearded dragon is placed in a plexiglass fronted enclosure after placement of the electrodes and Doppler probe, and administration of the drug (or saline), allowing 30 minutes (2 hours in case of oral administration) of quiet rest before the electrostimulation begins. The plexiglass enclosure is preheated with lights to a constant temperature before the lizard is placed in the enclosure and the temperature is monitored and recorded every 5 minutes during the entire procedure. Statistical analysis of response scores will be analyzed using mixed model analysis of variance (ANOVA). Our statistician suggested 20 bearded dragons for the proposed study based on power tests performed using information gained from the preliminary study. The body scores from our previous study had a coefficient of variation of 70%. Given a mean body score of 2, this leads to an estimate of 2.70 +/-1.4 for standard deviation, which also matches the variance estimates from the ANOVA. Thus, assuming the coefficient of variation of the proposed study is 70% as in the previous study, then to be 80% sure of detecting a difference of 1 unit on the body movement scale would require a sample size of 22 at a 0.05 significance level. With the bearded dragons having a more consistent temperament than the iguanas, we would expect the coefficient to be even lower, and thus more power allowing the use of 20 animals.