receptors (e.g., ANS) Flashcards
alpha 1
located mostly in postsynaptic effector cells found in smooth muscle; effects mediated by IP3/DAG path, include mydriasis due to contraction of radial muscles, constriction of arteries and veins, urinary retention due to internal/external urethral sphincter contraction, and a decrease in renin release from renal juxtaglomerular cells
alpha 2
located in presynaptic adrenergic terminals found in lipocytes and smooth muscle; effects mediated by decreasing cAMP, including a decrease in norepinephrine release, stimulates platelet aggregation and decreases insulin secretion
beta 1
located in postsynaptic effector cells in the SA node of the heart, lipocytes, brain, juxtaglomerular apparatus of renal tubules, and the ciliary body epithelium; effects mediated by increasing cAMP, including increased heart rate and the conduction velocity through the cardiac nodes, also increases renin release from renal juxtaglomerular cells
beta 2
located in postsynaptic effector cells in smooth muscle and cardiac myocytes; effects mediated by increasing cAMP, include vasodilation, bronchiole dilation, increased insulin secretion, and uterine relaxation
beta 3
located in postsynaptic effector cells in lipocytes and myocardium; similar effects to beta-1 receptors mediated by increasing cAMP
muscarinic 1
(M1)
important to note is the only cholinoreceptor involved in an SNS process, located in sweat glands of the skin; effects mediated by IP3/DAG path, include glandular contraction and increased secretion
muscarinic 2
(M2)
located in SA and AV nodes and myocardium; effects mediated by decreasing cAMP, include decreasing heart rate and myocardial conduction velocity
muscarinic 3
(M3)
located in the smooth muscle of various organ systems; effects mediated by IP3/DAG path, include contraction of the ciliary muscle causing miosis, contraction of bronchioles, increased bronchiole secretions, increased GI motility, detrusor muscle contraction, and internal/external urethral sphincter relaxation
muscarinic 4 (M4) and muscarinic 5 (M5)
located primarily in the CNS, e.g., forebrain and substania nigra, respectively
nicotinic N
(NN)
located in postsynaptic dendrites of both sympathetic and parasympathetic postganglionic neurons; effects mediated by Na+/K+ depolarization, include increased neurotransmission
nicotinic M
(NM)
located in neuromuscular endplates of skeletal muscle; effects mediated by Na+/K+ depolarization, include skeletal muscle contraction
dopamine 1 - 5
(D1 - 5)
located in the CNS, except for Dopamine-1 receptors, which also appear in renal vasculature; effects mediated by cAMP path, include renal artery vasodilation, increased renal blood flow, and modulation of neuroendocrine signaling
misc major effects of adrenergic receptors
Alpha-1 receptor: Smooth muscle contraction, mydriasis
Alpha-2 receptor: Mixed smooth muscle effects
Beta-1 receptor: Increased cardiac chronotropic and inotropic effects
Beta-2 receptor: Bronchodilation
Beta-3 receptor: Increased lipolysis
alpha 1 receptor AGONIST examples
phenylephrine
oxymetazoline
alpha 2 receptor AGONIST examples
methyldopa
clonidine
dexmedetomidine
beta 1 receptor AGONIST examples
dobutamine
beta 2 receptor AGONIST examples
bronchodilators
beta 3 receptor AGONIST examples
mirabegron:
indicated for treating overactive bladder, e.g., urinary incontinence and frequency. also indicated to treat pediatric (>/= 3 years old) neurogenic detrusor overactivity
non-selective drugs
Norepinephrine: Indicated for the treatment of shock and hypotension
Epinephrine (Adrenaline): Indicated for the treatment of cardiac arrest, anaphylaxis, and croup
Dopamine: Indicated for the treatment of hypotension, bradycardia, and cardiac arrest
Isoprenaline: Indicated for treating bradycardia and heart block
[Many of these medications, especially the non-selective ones, are used in critical care and emergency settings. They are referred to as vasopressors. Side effects depend on the specific agent. However, changes in heart rate and blood pressure are the most common side effects.
Indirect-acting adrenergic drugs increase endogenous concentrations of norepinephrine and epinephrine through various mechanisms. Hence, their side effect profiles are similar to those seen with vasopressors.]
acebutolol
B1 (cardio selective)
atenolol
B1 (cardio selective)
betaxolol
B1 (cardio selective)
bisoprolol
B1 (cardio selective)
esmolol
B1 (cardio selective)
This medication is only available in an IV form, which limits its use to hospitals and similar medical settings.
