(noradrenaline) Although complete selectivity between receptor agonism is rarely achieved, some agents have partial selectivity. NB: the inclusion of a drug in each category just indicates the activity of the drug at that receptor, not necessarily the selectivity of the drug (unless otherwise noted).
α1 agonist α1 agonist: stimulates
phospholipase C activity. (vasoconstriction and mydriasis; used as vasopressors, nasal decongestants and during eye exams). Selected examples are: • Adrenoswitch-1 (photoswitchable partial α1 agonist and light-controlled mydriatic) •
Methoxamine •
Midodrine •
Metaraminol •
Phenylephrine •
Amidephrine • Sdz-nvi-085 [104195-17-7].
α2 agonist α2 agonist: inhibits
adenylyl cyclase activity, reduces brainstem vasomotor center-mediated CNS activation; used as
antihypertensive,
sedative & treatment of
opiate dependence and
alcohol withdrawal symptoms). Selected examples are: •
Agmatine •
Brimonidine •
Clonidine (mixed alpha2-adrenergic and
imidazoline-I1 receptor agonist) •
Dexmedetomidine •
Fadolmidine •
Guanfacine, (preference for alpha2A-subtype of adrenoceptor) •
Guanabenz (most selective agonist for alpha2-adrenergic as opposed to imidazoline-I1) •
Guanoxabenz (metabolite of guanabenz) •
Xylazine (not approved for human use) •
Tizanidine •
Methyldopa •
Methylnorepinephrine •
Norepinephrine •
(R)-3-nitrobiphenyline, an α2C selective agonist as well as a weak
antagonist at the α and α subtypes. •
Amitraz •
Detomidine •
Lofexidine, an
α2A adrenergic receptor agonist. •
Medetomidine, an α2
adrenergic agonist. •
Tasipimidine Nonspecific agonist Nonspecific agonists act as agonists at both alpha-1 and alpha-2 receptors. •
Xylometazoline •
Oxymetazoline •
Apraclonidine •
Cirazoline •
Epinephrine Undetermined/unsorted The following agents are also listed as agonists by
MeSH. •
Ergotamine •
Etilefrine •
Indanidine •
Mephentermine •
Metaraminol •
Methoxamine •
Mivazerol •
Naphazoline •
Norfenefrine •
Octopamine •
Phenylpropanolamine •
Propylhexedrine •
Rilmenidine •
Romifidine •
Synephrine •
Talipexole ==Clinical significance==