[5] Adrenergic Receptors Flashcards
Rate Limiting Step of Norepinephrine
Tyrosine Hydroxylase
Tyrosine -> DOPA
Receptors prolific in smooth muscles and blood vessels
Alpha-1
Postsynaptic effector mostly found in the heart
Beta-1
Postsynaptic effector cells especially in smooth muscles
Beta-2
Postsynaptic effector cells especially in lipocytes
Beta-3
Which has a methyl group? Epinephrine or Norepinephrine?
Epinephrine
because
NO-repinephrine
Subtypes of Beta-1 Receptors
Heart
Juxtaglomerular cell
Subtypes of Beta-2Receptors
Respiratory, uterine, and vascular smooth muscle
Skeletal Muscle
Human Liver
Function: Activation of Beta-2 in Respiratory Tissue
Smooth muscle relaxation
Function: Activation of Beta-2 in Skeletal Muscle
Potassium Uptake
Function: Activation of Beta-2 in the Liver
Activates glycogenolysis
Function: Activation of Beta-3 Receptors
Increased lipolysis
Receptor Specificity is ____ but not _____?
Relative, but not absolute
Parent Compound of Adrenergic Agents
Phenylethylamine
Effect: Increased size of alkyl substituents on Amino Group
Increased beta-receptor activity
Decreased alpha-receptor activity
A lower Kd value would mean?
Higher potency
Effect: Decreased substitution of benzene ring
Increased bioavailability and prolongs duration of action
Since they are not catecholamines, they are spared from COMT Inactivation in the Gut and Liver
Effect: Substitution on the Alpha Carbon
Prolonged action of drugs especially in noncatecholamines
Effect: Substitution on the Beta-Carbon
Important for storage
Relative Selectivity of Adrenoceptor Agonists
Alpha Agonists
Phenylephrine, Midodrine
Alpha 1 > Alpha 2»_space;»> Beta
Me-dodrine, me is 1
Relative Selectivity of Adrenoceptor Agonists
Alpha Agonists
Clonidine, Methylnorepinephrine
Alpha 2 > Alpha 1»_space;»> Beta
Clone ni Din, so they are 2
Beta-1 Receptor Agonist Effect as a:
Chronotrope
Intrope
C: +
I: +
What receptor agonists do you use for Congestive Heart Failure and Cardiogenic Shock
Beta-1 Receptor
Classification of Dobutamine
Complex
( + ) Isomer: Alpha 1 Antagonist ; Beta-1 Agonist
( - ) Potent Alpha 1 Agonist
Function: Alpha-1 Receptor Agonists
Constriction smooth muscles causing increased peripheral resistance and venous return
Are there Alpha-1 receptors in the heart?
Yes
How come if you give a lot of epinephrine it actually causes decreased heart rate instead of increased?
Reflex Baroreceptor Vagal Discharge
Function: Alpha-2 Receptor Agonist
Reduce blood pressure
Classification of Clonidine
Alpha-2
Classification of Methyldopa
Alpha-2
Me-thoo
Classification of Phenylephrine
Alpha-1
Function: Alpha and Beta receptor agonists in GI Tract
Relax gastrointestinal smooth muscle
Function: Alpha-2 Selective Agonists in GI Tract
Enhanced salt and water reabsorption
Treatment of diarrhea, Clonidine
Function: Beta-2 Receptor Agonist in Genitourinary Tract
Relax smooth muscle
Relaxation of bladder wall
Function: Alpha-1 Agonist in Genitourinary Tract
Constriction of bladder base, urethral sphincter
Which receptor causes increased lipolysis in fat cells?
Beta-3
3 layers of fat
Which receptor causes increased insulin uptake?
Beta-2
In-THWOO-Lin, pretend may lithp ka
Effect: Amphetamine
Non-exocytotic release of Norepinephrine
It is taken up by NET and blocks MAO
Examples of Alpha-1 Receptor Antagonists
Prazosin
Terzosin
Doxazosin
(They are SIN-ners, antagonists to Alpha-1)
What is Tamsulosin used for?
Benign Prostatic Hypertrophy
Binds better to A and D better than B so it is used for this instead of for hypertension
Is Epinephrine selective or non-selective?
Non-Selective
Prototypic non-selective beta blocker
Propranolol
Prototypic selective beta blocker
Metoprolol
What are the selective B-Agonists?
A BEAM of B1-Blocker
Acebutolol Betaxolol Esmolol Atenolol Metoprolol
Examples of Partial Agonists
Pindolol
Acebutulol
(Eh, why not Atenolol? Dahil hindi raw partial si Ate.)
