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Affinity of detomidine, medetomidine and xylazine for alpha‐2 adrenergic receptor subtypes
Author(s) -
Schwartz D.D.,
Clark T.P.
Publication year - 1998
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1046/j.1365-2885.1998.00113.x
Subject(s) - detomidine , medetomidine , xylazine , alpha 2 adrenergic receptor , adrenergic receptor , alpha (finance) , receptor , adrenergic , medicine , anesthesia , surgery , heart rate , ketamine , construct validity , blood pressure , patient satisfaction
α 2 ‐Adrenergic receptor agonists are widely used in veterinary medicine as sedative/hypnotic agents. Four pharmacological subtypes of the α 2 ‐adrenergic receptor (A, B, C and D) have been identified based primarily on differences in affinity for several drugs. The purpose of this study was to examine the affinities of the sedative agents, xylazine, detomidine and medetomidine at the four α 2 ‐adrenergic receptor subtypes. Saturation and inhibition binding curves were performed in membranes of tissues containing only one subtype of a 2 ‐adrenergic receptor. The K D for the α 2 ‐adrenergic receptor radioligand, [ 3 H]‐MK‐912, in HT29 cells (α 2A ‐), neonatal rat lung (α 2B ‐), OK cells (α 2C ‐) and PC12 cells transfected with RG20 (α 2D ‐) were 0.38 ± 0.08 n m , 0.70 ± 0.5 n m , 0.07 ± 0.02 n m and 0.87 ± 0.03 n m , respectively. Detomidine and medetomidine had approximately a 100 fold higher affinity for all the α 2 ‐adrenergic receptors compared to xylazine but neither agonist displayed selectivity for the α 2 ‐adrenergic receptor subtypes. These data suggest that available sedative/hypnotic α 2 ‐adrenergic receptor agonists can not discriminate between the four known α 2 ‐adrenergic receptor subtypes.