Introduction to Autonomic Pharmacology Flashcards
Parasympathetic synapses
Ist: ACh to nAChR
2nd: ACh to mAChR
Sympathetic synapses
Ist: ACh to nAChR
2nd: NE, DA, ACh to alpha, beta, D, nAChR and mAChR
Epinephrine synthesis
Synthesis occurs in the adrenal medulla and a few pathways in the brainstem.
DA acts on (2):
CNS and renal vascular smooth muscle
nAChR Receptor Tissue Function Agonists
Ionotropic
CNS, autonomic ganglia, adrenal medulla
Excitatory, release of catecholamines
ACh, nicotine
mAChR Receptor Tissue Function Agonists
Metabotropic
CNS, autonomic ganglia, effector organs, sweat glands
Excitatory and inhibitory, sweat secretion
ACh, muscarine
Gq M receptors (3):
M1, M3, M5
Excitatory
Gi M receptors (2):
M2, M4
Inhibitory
Reuptake in an adrenergic synapse vs. cholinergic synapse
Adrenergic: NE is brought back into the presynaptic cell.
Cholinergic: ACh is destroyed in the synapse.
Catecholamine synthesis
Incytoplasm: Tyr -> Dopa -> Dopamine -> In adrenal medulla: NE -> Epi
Na+-dependent tyr transporter
Transports tyr into the nerve terminal.
VMAT-2
Transports NE, Epi, DA and serotonin into vesicles.
Releases them upon Ca 2+ influx
NET
DAT
Imports NE into nerve terminal.
Imports DA into nerve terminal.
Enzymes responsible for metabolism of catecholamines (2)
MAO
COMT
Alpha 1 subtype
Responds to:
Tissues:
Action:
Epi >/ NE
GI SM, heart
Contraction, hyperpolarization and relaxation. Increased contractile force.
Exitatory
Alpha 2 subtype
Responds to:
Tissues:
Action:
Epi >/ NE
Pancreatic beta cells, platelets, vascular SM, nerve terminals.
Decreased insulin secretion, decreased release of NE, contraction.
Inhibitory
Beta 1 subtype
Responds to:
Tissues:
Action:
Epi = NE
Juxtaglomerular cells, heart
Increased renin, increased force and rate of contraction, increased AV nodal velocity
Beta 2 subtype
Responds to:
Tissues:
Action:
Epi»_space; NE
SM (vascular, bronchial, GI, GU), skeletal muscle
Relaxation, glycogenolysis
Alpha 1 receptor overview
Stimulates contraction of smooth muscle.
Beta 2 receptor overview
Relax smoth muscle.
Muscarinic receptor overview
Contract smooth muscle (but a different IC signaling than alpha 1).
How does the PSNS affect BVs?
It does not have receptors on BVs, but it can act on endothelium to cause NO synthesis and vasodilation.
There are no ____ on SM in BVs?
mAChR and nAChR
EDRF
mAChR activated on endothelial cells and causes its release (same thing as NO).
Adrenal medulla release of Epi, NE
ACh from preganglionic fibers binds NnAChR and causes localized depolarization.
Release is approx. 80% Epi and 20% NE.
Sympathomimetic agents
Drugs that mimic or enhance a and B receptor stimulation.
Beta-1 think mainly____
Beta-2 think mainly____
Heart
Lungs
