Effects of buprenorphine on nociception and spontaneous locomotor activity in horses.
OBJECTIVE
To investigate spontaneous locomotor activity (SLA) and antinociceptive effects of buprenorphine in horses.


METHODS
6 healthy adult horses.


METHODS
Horses received each of 3 treatments (10 mL of saline [0.9% NaCl] solution, 5 microg of buprenorphine/kg, or 10 microg of buprenorphine/kg). Treatments were administered IV. Order of treatments was randomized, and there was a 10-day interval between subsequent treatments. Spontaneous locomotor activity was investigated in a behavioral box by use of infrared photoelectric sensors connected to a computer, which detected movement of each horse. Antinociceptive effect was investigated by hoof-withdrawal reflex latency (HWRL) and skin-twitching reflex latency (STRL) after painful stimulation with a heat lamp.


RESULTS
Moderate excitement was observed in all horses from 5 to 10 minutes after the administration of both dosages of buprenorphine. The SLA increased significantly for 6 and 14 hours after IV administration of 5 and 10 microg of buprenorphine/kg, respectively. Values for HWRL increased significantly only at 30 minutes after injection of 5 microg of buprenorphine/kg, whereas STRL and HWRL each increased significantly from 1 to 6 hours (except at 2 and 4 hours) and 11 hours, respectively, after injection of 10 microg of buprenorphine/kg.


CONCLUSIONS
IV injection of buprenorphine caused a dose-dependent increase in SLA, but only the dose of 10 microg/kg induced analgesia on the basis of results for the experimental method used.
Carregaro
Adriano B
AB
School of Veterinary Medicine and Animal Science, University of São Paulo State, Botucatu, Brazil 18618-000.
Luna
Stelio P L
SP
Mataqueiro
Maria Isabel
MI
de Queiroz-Neto
Antonio
A
D000701:Analgesics, Opioid / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D002047:Buprenorphine / Q000494:pharmacology* / Q000627:therapeutic use; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006736:Horses / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D010146:Pain / Q000188:drug therapy / Q000503:physiopathology*; D010147:Pain Measurement / Q000662:veterinary*; D013997:Time Factors
D000701:Analgesics, Opioid; D002047:Buprenorphine