Autonomic Nervous System: Adrenoreceptors Flashcards
what are Adrenoreceptors?
all G-protein coupled receptors
what are the 2 types of Adrenoreceptors?
2 main alpha
3 main beta
what are the effects of α adrenoreceptors?
α1 and α2 - smooth muscle constriction
α1 - iris radial muscle contraction
increase in BP and reflex bradycardia
predominantly vascular
what are the effects of β adrenoreceptors?
β2 - dilation of uterus and bronchial tissue
ciliary muscle
small arteries to skeletal muscle
histamine release from mast cells
β1 - glycogenolysis (+ α)
what are the selective adrenoreceptor alpha agonists?
α1Phenylephrine
α2 Clonidine, Xylazine
what are the selective adrenoreceptor beta agonists?
β1 Dobutamine
β2 Salbutamol, Terbutaline
what are non-selective alpha adrenoreceptor agonists?
α1 and α2 - Methoxamine, Oxymetazoline
Adrenaline and Noradrenaline
what are the non-selective beta adrenoreceptor agonists?
β1 and β2 - Isoprenaline
uses of adrenoreceptor agonists in clinic for Cardiovascular System
Adrenaline β for cardiac arrest
Dobutamine β for cardiac shock
Isoprenaline β for heart block
Methoxamine α for hypotensive crisis
uses of adrenoreceptor agonists in clinic for Anaphylactic Reactions
adrenaline β 2
uses of adrenocreceptor agonists for Respiratory System
selective β2 agonists for Asthma
vasoconstriction to relieve nasal
decongestion (oxymetazoline via α1)
(rhinitis medicamentosa)
other uses of adrenoreceptor agonists
Clonidine α2 for hypertension, flushing, migraine (low efficacy)
side effects of adrenoreceptor agonists
β2 agonists - tremor, headache, peripheral dilatation and palpitations tachycardia and arrhythmias.
β1 agonists (Inotropic sympathomimetics) - Tachycardia & BP rise.
α agonists (vasoconstrictor sympathomimetics) - hypertension, headache, bradycardia, arrhythmias
