DSA- Pharmacology Autonomics Flashcards
Neurotransmitters of ANS (5)
- Acetylcholine
- Norephinephrine
- Epinephrine
- Dopamine
- Co-transmitters
Acetylcholine
- PNS
- SNS
- receptors
major NT of PNS
- found in all PREganglionic fibers
- found in all POSTganglionic PARAsympathetic fibers
nicotinic and muscarinic
Norepinephrine
- receptors
major NT of SNS
- found in majority of POSTganglionic SYMpathetic fibers
catecholamine
Epinephrine
- synthesis
- receptor
only occurs in adrenal medulla
depolarization of preganglionic sympathetic neuron (cholinergic)
nicotinic
catecholamine
Dopamine
- receptor
precursor to NE and Epi
synthesized in cytoplasm of neurons
has actions in CNS and renal vascular smooth muscle
catecholamine
Co-transmitters (4)
ATP
Neuropeptide Y
Substance P
Vasoactive intestinal Peptide (VIP)
Cholinergic Neurotransmission components steps
- Synthesis of ACh
- Storage of ACh
- Release of AcH
- Binding to cholinergic receptors
- Termination of acetylcholine signaling
Synthesis of ACh
Choline transporter transport choline into neuron
Choline + AcoA (choline acetyletransferae (ChAT))-> ACh
Storage of ACh
ATPase-dependent ACH vesicular transporter puts ACh into vesicles
Release of Ach
AP-> depolarization causes Ca2+ voltage gated channels to open -> Ca2+ enter neuron -> vesicle go to cell membrane -> SNARE protein complex fuse vesicle into membrane ( VAMPS, SNAPS)
Binding of ACh to cholinergic neurons
- effects
Ach diffused into synaptic cleft adn bind to nAChR
- activation of release of Epi, NE
- smooth muscle contraction
- glandular secretion
- decrease heart rate
Termination of acetylcholine signaling
Acetylcholinesterase (AChE) cleaves ACh into acetate and choline
ACh-> choline + acetate
Botulin Toxin
prevent ACh vesicle from being released into synaptic cleft
Vesamicol
prevent storage of AcH in neuron
- ATPase-dependent ACH vesicular transporter
Hemicholinium
prevent choline from reuptake into neuron
M1
- location
- structural feature
- mechanism
ACh receptor
Location: CNS, ganglia
structure: Gq
Mechanism: activation PLC, DAG, IP3
M2
- location
- structural feature
- mechanism
ACh receptor
Location: heart, nerve , smooth muscle
structure: Gi
Mechanism: inhibit AC, activate K channel
M3
- location
- structural feature
- mechanism
ACh receptor
Location: Glands, smooth muscle, endothelium
structure: Gq
Mechanism: activation PLC, DAG, IP3
M4
- location
- structural feature
- mechanism
ACh receptor
Location: CNS
structure: Gi
Mechanism: inhibit AC/ CAMP,
activate K channel
M5
- location
- structural feature
- mechanism
ACh receptor
Location: CNS
structure: Gq
Mechanism: activate PLC, IP3, DAG
Nm
- location
- structural feature
- mechanism
ACh receptor
Location: skeletal muscle, NMJ
structure: ligand-gated ion channel
Mechanism: Na/K depolarizing ion channels
Nn
- location
- structural feature
- mechanism
ACh receptor
Location: Postganglionic cell body, CNS, dendrite
structure: ligand-gated ion channel
Mechanism: Na/K depolarizing ion channels
adrenergic transmission
catecholamines
- NE
- EPI
- DA
Synthesis of catecholamines
Tyrosine is transported into nerve terminal
Adrenal medulla
storage of catecholamines
Vesicular monamine transporter (VMAT2)
in cytoplasm
Tyrosine-> DOPA-> DA
Reserpine
drug that inhibits VMAT2
-leads to depletion of catecholamines from sympathetic nerve
Release of catecholamines
Ca2+ influx in adrenal medulla-> release ACh and bind with nAChR on chromaffin cells
Binding of catecholamines to adrenergic receptors
bind to alpha or beta receptor
- stimulatory or inhibitory
- glycogenesis, gluconeogenesis, relaxation, etc
Termination of catecholamin signaling ( 2)
- NET (norephinephrine transporter) and DAT (dopamine transporter) reuptake and store in vesicles via VMAT2
- Diffusion and uptake at extraneuronal sites via transporter ENT, OCT1, OCT2 by two enzymes
- monoamine oxidase (MAO):
- Catechol-o-methyltransferase (COMT: in liver
Cocaine
inhibit NE reuptake into neuron
Alpha 1 receptors
-effects
contraction of SM
vasoconstriction
glandular SM secretion
pupil dilation
uterine contraction
B2 receptors
-effects
stimulate relaxation of all SM
tracheal and bronchial SM relaxation
uterine SM relaxation
intestinal SM relaxation
vasodilation
Muscarinic receptor
- effect
contraction of all SM
contraction of iris sphincter muscle
contraction of bladder, interstinal SM,
DECREASE HR
ACh/ NO stimulation
EDRF (Nitric Oxide)
short lived vasodilator
- in response to an AP, parasympathetic neurons release ACh _> activate mAChR -> produce NO-> go to blood vessel to cause relaxation
Parasympathetic (cholinergic) effects
- salivation
- Lacrimination
- Pupil constriction
- decrease HR
- Uriniation
- Increased secretions
- Increase GI motility
Sympathetic (adrenergic) effects
- pupil dilation
- increase HR
- Urinary retention
- decreased secretion
- decreased GI motility
Baroreceptor Reflex
- increase BP (Phenylephrine)
- Increase baroreceptor
- increase PNS
- decrease SNS - decrease BP
- decrease baroreceptors
- decrease PNS
- increase SNS
