Unit 3- Adrenergic Agonists Flashcards
Sympathomimetic
Mimic effects of catecholamines, dependent on similarity of structure to NE and EPI
Direct Acting Agonists
Endogenous catecholamines, adrenergic receptor agonists
Indirect Acting Antagonists
Trigger catecholamine release, reduce metabolism, or inhibit reuptake
Mixed Acting Antagonists
Directly activate adrenergic receptors while increasing NE release
Desensitization
Reduced response of receptors to an agonist after prolonged exposure, reducing physiological response
Causes of Desensitization
Sequestration of receptors, destruction or decreased synthesis of receptors, receptor being phosphorylated and unable to couple to G-protein
α1 Agonists
EPI, NE, phenylephrine
α2 Agonists
EPI, NE, medetomidine, xylazine
β1 Agonists
EPI, NE, isoproterenol, dobutamine
β2 Agonists
EPI, ractopamine, isoporterenol, terbutaline
Phenylephrine Selectivity
α1
Dexmedetomidine Selectivity
α2
Xylazine Selectivity
α2
NE Selectivity
α>β1
EPI Selectivity
All receptors equal
Dobutamine Selectivity
β1
Isoproterenol Selectivity
β
Albuterol Selectivity
β2
Terbutaline Selectivity
β2
Dopamine Selectivity
D>β