Analgesic efficacy of butorphanol and morphine in bearded dragons and corn snakes

Kurt K. Sladky Department of Surgical Sciences and the Conservation Health Consortium, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Kurt K. Sladky in
Current site
Google Scholar
PubMed
Close
 MS, DVM, DACZM
,
Matthew E. Kinney Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Matthew E. Kinney in
Current site
Google Scholar
PubMed
Close
 BS
, and
Stephen M. Johnson Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706.

Search for other papers by Stephen M. Johnson in
Current site
Google Scholar
PubMed
Close
 MD, PhD

Click on author name to view affiliation information

Abstract

Objective—To test the hypothesis that administration of butorphanol or morphine induces antinociception in bearded dragons and corn snakes.

Design—Prospective crossover study.

Animals—12 juvenile and adult bearded dragons and 13 corn snakes.

Procedures—Infrared heat stimuli were applied to the plantar surface of bearded dragon hind limbs or the ventral surface of corn snake tails. Thermal withdrawal latencies (TWDLs) were measured before (baseline) and after SC administration of physiologic saline (0.9% NaCl) solution (equivalent volume to opioid volumes), butorphanol tartrate (2 or 20 mg/kg [0.91 or 9.1 mg/lb]), or morphine sulfate (1, 5, 10, 20, or 40 mg/kg [0.45, 2.27, 4.5, 9.1, or 18.2 mg/lb]).

Results—For bearded dragons, butorphanol (2 or 20 mg/kg) did not alter hind limb TWDLs at 2 to 24 hours after administration. However, at 8 hours after administration, morphine (10 and 20 mg/kg) significantly increased hind limb TWDLs from baseline values (mean ± SEM maximum increase, 2.7 ± 0.4 seconds and 2.8 ± 0.9 seconds, respectively). For corn snakes, butorphanol (20 mg/kg) significantly increased tail TWDLs at 8 hours after administration (maximum increase from baseline value, 3.0 ± 0.8 seconds); the low dose had no effect. Morphine injections did not increase tail TWDLs at 2 to 24 hours after administration.

Conclusions and Clinical Relevance—Compared with doses used in most mammalian species, high doses of morphine (but not butorphanol) induced analgesia in bearded dragons, whereas high doses of butorphanol (but not morphine) induced analgesia in corn snakes.

Abstract

Objective—To test the hypothesis that administration of butorphanol or morphine induces antinociception in bearded dragons and corn snakes.

Design—Prospective crossover study.

Animals—12 juvenile and adult bearded dragons and 13 corn snakes.

Procedures—Infrared heat stimuli were applied to the plantar surface of bearded dragon hind limbs or the ventral surface of corn snake tails. Thermal withdrawal latencies (TWDLs) were measured before (baseline) and after SC administration of physiologic saline (0.9% NaCl) solution (equivalent volume to opioid volumes), butorphanol tartrate (2 or 20 mg/kg [0.91 or 9.1 mg/lb]), or morphine sulfate (1, 5, 10, 20, or 40 mg/kg [0.45, 2.27, 4.5, 9.1, or 18.2 mg/lb]).

Results—For bearded dragons, butorphanol (2 or 20 mg/kg) did not alter hind limb TWDLs at 2 to 24 hours after administration. However, at 8 hours after administration, morphine (10 and 20 mg/kg) significantly increased hind limb TWDLs from baseline values (mean ± SEM maximum increase, 2.7 ± 0.4 seconds and 2.8 ± 0.9 seconds, respectively). For corn snakes, butorphanol (20 mg/kg) significantly increased tail TWDLs at 8 hours after administration (maximum increase from baseline value, 3.0 ± 0.8 seconds); the low dose had no effect. Morphine injections did not increase tail TWDLs at 2 to 24 hours after administration.

Conclusions and Clinical Relevance—Compared with doses used in most mammalian species, high doses of morphine (but not butorphanol) induced analgesia in bearded dragons, whereas high doses of butorphanol (but not morphine) induced analgesia in corn snakes.

All Time Past Year Past 30 Days
Abstract Views 390 0 0
Full Text Views 1111 867 144
PDF Downloads 538 289 16
Advertisement