Skip to main content
SLU publication database (SLUpub)

Abstract

Xylazine is an alpha (2) -adrenoceptor agonist sedative with a much higher interspecies variability in effect than detomidine, another alpha (2) -agonist used in veterinary practice. In the present study, we have used radioligand binding in brain tissue to investigate if the high species variation in sensitivity to xylazine could be explained in terms of receptor interactions. Species known to be more (cattle) or less (swine and rats) sensitive to xylazine were used. There was no variation in the density or the subtype pattern of the alpha (2) -adrenoceptors that could explain the species variation recorded in vivo , as a homogenous population of the alpha (2A/D) -subtype (200-300 fmol/mg protein) was found in all species. The species differences in the affinities of xylazine and detomidine were minor and similar for the two drugs. The only parameter investigated where a significant species difference was found for xylazine but not for detomidine was the slope of the inhibition binding curve when the G-protein coupling was diminished. For xylazine this slope was considerably lower than unity (i.e. 0.77 +/- 0.075) using cattle preparations compared with 0.92 +/- 0.037 (mean +/- SE) and 0.90 +/- 0.028, respectively for swine and rats, while for detomidine this parameter was close to unity in all species (cattle, swine, rat). This finding indicates that the species variation in effect for xylazine could be due to differences at the G-protein level or further down-stream in the effect cascade

Keywords

xylazine; detomidine adreno alfa2-adrenoceptors

Published in

Journal of Veterinary Pharmacology and Therapeutics
2003, volume: 26, number: 3, pages: 205-211
Publisher: BLACKWELL PUBLISHING LTD

SLU Authors

UKÄ Subject classification

Pharmacology and Toxicology

Publication identifier

  • DOI: https://doi.org/10.1046/j.1365-2885.2003.00466.x

Permanent link to this page (URI)

https://res.slu.se/id/publ/1184