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
