Alpha-adrenoceptor agonistic activity of oxymetazoline and xylometazoline.
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Haenisch B, Walstab J, Herberhold S, Bootz F, Tschaikin M, Ramseger R, Bonisch H
Alpha-adrenoceptor agonistic activity of oxymetazoline and xylometazoline.
Fundam Clin Pharmacol. 2010 Dec;24(6):729-39. doi: 10.1111/j.1472-8206.2009.00805.x.
- PubMed ID
- 20030735 [ View in PubMed]
- Abstract
Oxymetazoline and xylometazoline are both used as nasal mucosa decongesting alpha-adrenoceptor agonists during a common cold. However, it is largely unknown which of the six alpha-adrenoceptor subtypes are actually present in human nasal mucosa, which are activated by the two alpha-adrenoceptor agonists and to what extent. Therefore, mRNA expression in human nasal mucosa of the six alpha-adrenoceptor subtypes was studied. Furthermore, the affinity and potency of the imidazolines oxymetazoline and xylometazoline at these alpha-adrenoceptor subtypes were examined in transfected HEK293 cells. The rank order of mRNA levels of alpha-adrenoceptor subtypes in human nasal mucosa was: alpha(2A) > alpha(1A) >/= alpha(2B) > alpha(1D) >/= alpha(2C) >> alpha(1B) . Oxymetazoline and xylometazoline exhibited in radioligand competition studies higher affinities than the catecholamines adrenaline and noradrenaline at most alpha-adrenoceptor subtypes. Compared to xylometazoline, oxymetazoline exhibited a significantly higher affinity at alpha(1A) - but a lower affinity at alpha(2B) -adrenoceptors. In functional studies in which adrenoceptor-mediated Ca(2+) signals were measured, both, oxymetazoline and xylometazoline behaved at alpha(2B) -adrenoceptors as full agonists but oxymetazoline was significantly more potent than xylometazoline. Furthermore, oxymetazoline was also a partial agonist at alpha(1A) -adrenoceptors; however, its potency was relatively low and it was much lower than its affinity. The higher potency at alpha(2B) -adrenoceptors, i.e. at receptors highly expressed at the mRNA level in human nasal mucosa, could eventually explain why in nasal decongestants oxymetazoline can be used in lower concentrations than xylometazoline.
DrugBank Data that Cites this Article
- Drugs
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Oxymetazoline Alpha-1A adrenergic receptor Protein Humans YesPartial agonistDetails Oxymetazoline Alpha-1B adrenergic receptor Protein Humans UnknownAgonistDetails Oxymetazoline Alpha-1D adrenergic receptor Protein Humans UnknownAgonistDetails Oxymetazoline Alpha-2B adrenergic receptor Protein Humans YesAgonistDetails Oxymetazoline Alpha-2C adrenergic receptor Protein Humans UnknownAgonistDetails Xylometazoline Alpha-1A adrenergic receptor Protein Humans YesAgonistPartial agonistDetails Xylometazoline Alpha-1B adrenergic receptor Protein Humans UnknownAgonistDetails Xylometazoline Alpha-1D adrenergic receptor Protein Humans UnknownAgonistDetails Xylometazoline Alpha-2A adrenergic receptor Protein Humans YesAgonistDetails Xylometazoline Alpha-2B adrenergic receptor Protein Humans YesAgonistDetails Xylometazoline Alpha-2C adrenergic receptor Protein Humans UnknownAgonistDetails