Adrenoreceptors Flashcards
(18 cards)
what are the two classes of adrenoreceptors?
alpha and beta
what are the subclasses of alpha and beta
a1 and a2
b1,b2 and b3
what is the difference between the two subclasses of alpha receptors
(organisation and function)
a1: stimulatory and GqPCR
(increases Ca2+)
a2: inhibitory and GiPCR
(decreases CAMP and PKA)
what is the function and organization of beta receptors
stimulatory and GsPCR
what are the main effect of each subclass?
a1 : SM constriction
a2: inhibition of NT
b1: increases heart rate
b2: relaxation of SM (increases NA)
b3: thermogenesis
what subclasses have what second messenger model
a2 and b act on adenyl cyclase
a1 acts on phospholipase C
what is the second messenger model for adenyl cyclase (a2/b)
adenyl cyclase stimulates ATP->CAMP
CAMP activates protein kinase which phosphorylates a target
what is the second messenger model for phospholipase C (a1)
phospholipase C cleaves phosphatidyl inositol diphosphate to inositol triphosphate and diacyl glycerol
IP3 initiates Ca2+ release by SR
DAG activates kinases e.g. RhoA
what are the catecholeamines of adrenoreceptors
CATECHOLEAMINES:
NA (alpha mainly)
A (beta “)
Dopamine
isoprenaline
what are the direct agonists of adrenoreceptors
a1: phenylphrine
a2: clonidine
b1: Dobutamine
b2: salbutamol
b3: migrabegron
what are the indirect agonists of adrenoreceptors
Amphetamine
cocaine
what are the non-selective antagonists of alpha and beta
a: prazosin
b: Propanolol
what are the a1 antagonists
Phenoxybenzamine
phentolamine
Prazosin
doxazosin
what are the ‘mixed’ adrenogenic receptor antagonists
Labetalol and carvedilol
what are the a2 selective antagonists
yohimbine
what are the 1st gen beta blockers
propranolol
what are the 2nd gen beta blockers
atenolol
what are the 3rd gen beta blockers
labetalol and carvedilol
