Adrenergic Drugs Flashcards
_____ drugs modulate adrenergic transmission and primarily control the fx of the sympathetic nervous system.
____ activate adrenergic transmission by promoting the effects of norepinephrine/epinephrine/dopamine at adrenergic receptors in the sympathetic NS.
____ drugs inhibit adrenergic transmission and prevent the effects or NE/E/Dopamine at adrenergic receptors in the sympathetic NS.
Adrenergic
Adrenomimetics
Antiadrenergic
Direct acting adrenergic drugs produce their effects via ____ with adrenergic receptors.
Indirect acting adrenergic drugs produce their effects by ____ the concentration of NE at target receptors. They alter neurotransmitter concentrations at target site.
Direct action
Increasing or reducing
Where are alpha1 receptors located and what is their action?
Vascular smooth m: contraction
Pupillary dilator m: contraction/dilates pupil
Prostate: contraction
Heart: contracton
Where are alpha 2 receptors located and what is their action?
Postsynaptic CNS neurons: many actions
Platelets: aggregation
Adrenergic and cholinergic nerve terminals: inhibits transmitter release
Vascular smooth m: contraction
Fat cells: inhibits lipolysis
Where are beta 1 receptors located and what is their action?
Heart: contraction
Juxtaglomerular cells: increases rennin release
Where are beta 2 receptors located and what is their action?
Respiratory, uterine, vascular smooth m: relaxation
Skeletal m: K uptake (hypopolarization)
Liver: glycogenolysis, gluconeogenesis
Where are beta 3 receptors located and what is their action?
Bladder: relaxes detrusor m
Fat cells: activates lipolysis
Where are dopamine 1 and dopamine 2 receptors located and what is their action?
D1= smooth m: dilates renal blood vessels
D2= nerve endings: modulates transmitter release
What are the types and subtypes of adrenergic receptors?
What are their signal transduction pathways?
Alpha 1: a1A, a1B, a1D -> Gq -> phospholipase C -> release IP3/DAG -> release Ca/protein kinase C
Alpha 2: a2A, a2B, a2C -> Gi -> inhibit adenylyl cyclase -> decrease in cAMP
Beta: B1, B2, B3 -> Gs -> adenylyl cyclase -> increase in cAMP
Dopamine: D1, D2, D3, D4, D5 -> Gs, Gi, Gi, Gi, Gs (Gs=increase cAMP; Gi=decrease cAMP)
List the four types of direct acting adrenergic drugs and what specific drugs belong in each class.
Also list their selectivity at adrenergic receptor subtypes
Alpha: phenylephrine (a1), clonidine (a2)
Mixed alpha and beta: NE (a1/a2/B1), E (a1/a2/B1/B2)
Beta: dobutamine (B1), isoproterenol. (B1/B2), terbutaline (B2), albuterol (B2)
Dopamine: dopamine (D1), fenoldopam (D1)
List the four MOA of indirect acting adrenergic drugs and what specific drugs belong in each class.
Inhibits re-uptake of DA and NE: cocaine
Inhibit monoamine oxidase (MAO): selegiline, phenelzine
Reverse NE and DA uptake mechanisms and increase their release: amphetamines, methylphenidate, tyramine
Releasing agent and direct adrenergic receptor agonist: ephedrine (mixed between direct and indirect)
Epinephrine binds to what receptors in the heart and vessels?
What are their effects?
Alpha1, 2; beta 1,2
B1: increases heart contraction, heart rate, conduction at the AV node
Alpha 1 and B2: increases systolic BP, decrease diastolic BP and total peripheral vascular resistance, mean arterial pressure is unchanged
Alpha1: skin vessels and mucous membranes
Alpha1 and B2: skeletal m
Alpha 1 and D1: renal and cerebral
Epinephrine binds to what receptors in the lungs, skeletal muscle, kidneys, and liver?
What are their effects?
B2: relaxes bronchial m
Alpha 1: decreases bronchial secretion and congestion within bronchial mucosa
B2: muscle tremor, increases K uptake by skeletal m (promotes hypokalemia and decreases K excretion by kidneys)
B2: increases glycogenolysis and gluconeogenesis
B: increases lipolysis
B1: increases renin release
Norepinephrine binds to what receptors?
What are their effects?
Alpha1, alpha 2, beta 1
Reduces HR
Vasoconstrictor
Lacks B2 agonist effects therefore no bronchodilation and vasodilation
Increases peripheral vascular resistance and blood pressure
Baroreflex
What type of drug is phenylephrine? What are the pharmacodynamic effects?
Alpha adrenergic agonist (a1)
Effective mydriatic and decongestant
Causes severe vasoconstriction, blood pressure elevation, severe bradycardia
Role of baroreflex
What type of drug is clonidine? What are the pharmacodynamic effects?
Alpha 2 adrenergic agonist
Central effect on alpha2 receptors in the lower brainstem area
Decreases sympathetic outflow
Reduction in blood pressure
Bradycardia
Local application produces vasoconstriction
Regulation of NE release by presynaptic alpha2 adrenoceptors
What type of drug is isoproterenol? What are the pharmacodynamic effects?
Non-selective beta adrenergic agonist (B1, B2)
Positive inotropic and chronotropic action, increases cardiac output (B1)
Vasodilator, decreases arterial pressure (B2)
Bronchodilation (B2)