ANS DSA Flashcards
What’s part of the efferent portion of the nervous system?
somatic = conscious movements
ANS - unconscious… cardiac output, blood flow or organs, digestion.
ANS is subdivided by?
Sympathetic (thoracolumbar)
parasympathetic (craniosacral)
Parasympathetic vs sympathetic neurotransmitters?
receptors?
PNS: NT = ACh … activates both nACHr and mAChr
SNS: NT = (catecholamines) NE> Epi (dopamine); and Ach.
A, B adrenergic receptors, dopamine receptors, and mAChR and mAChR
Sweat glands are controlled by what? (SNS)
renal vascular smooth muscle (SNS)
Cardiac and smooth muscle, gland cells, nerve terminals? (SNS)
acetylcholine / muscarinic receptors
dopamine, dopaminergic receptors
NE, alpha and beta adrenergic
what’s the primary mediator for all ganglion nervous system independent of PNS or SNS?
Ach
What does Ach act on to release Epi/NE?
on the adrenal medulla via a nAChR receptor!
Acetylcholine is found where?
is it found at any postganglionic sympathetic fibers?
all preganglionic fibers and and all postganglionic PARASYMPATHETIC FIBERS
yes! Sweat glands
NE is what?
major Neurotransmitter of the SNS
vast majority of the postganglionic sympathetic fibers
Epinephrine?
only occurs in the adrenal medulla and in a few epi containing pathways in the brainstem
Dopamine?
acts on CNS and renal vascular smooth muscle.
this is a precursor to NE and Epi
Explain ACh
synthesized in the cytoplasm, shuttled into the vesicle and stored in a cholinergic varicosity.
as an AP comes down, Calcium flows into the cholinergic cell, causing fusion of the vesicle through VAMPS and SNAPS (SNARE complex).
after fusion the Ach is released where it can interact with mAChR or nAChR
Ach is then destroyed by acetylcholinesterase enzyme
nAChR vs mAChR… which one is ionotropic, which is metabotropic?
which one is found at the CNS + autonomic ganglia?
Which is found at the adrenal medulla?
which is found at the sweat glands?
which is found at the effector organs (cardiac and smooth muscle, gland cells, nerve terminals)
nAChR is ionotropic, mAChR is metabotropic.
Both
nAChR
mAChR
mAChR
what is the general function of nAChR?
what about for mAChR?
excitatory unless it’s with the adrenal medulla and that would be release of catecholamines
both excitatory and inhibitory unless it has to deal with the sweat glands and that would be sweat secretion
Agonists of nAChR?
mAChR?
ACh, Nicotine
ACh, Muscarine
Nm is found where?
Nn?
what structural features are these?
what is their mechanism?
skeletal muscle, neuromuscular junction
postganglionic cell body, dendrites, CNS
both ligand gated ion channels
both Na+, K+ depolarizing Ion Channels
M1 location?
M2 location?
M3 Location?
M4 + M5 location?
CNS, ganglia
heart, nerves, smooth muscle
glands, smooth muscle, endothelium
CNS
M1-M5 structural features?
what are they all similar with?
M1, M3, M5 = Gq
they’re all going to be activating phospholipase C (PLC), increasing IP3 and DAG cascades
M2/M4 = Gi/o.. inhibiting adenylyl cyclase (AC), lowering cAMP production, activation of K+ channels.
all are GPCR
what are the primary muscarinic subtypes that are found on organs?
mostly on smooth muscle?
M2 + M3
M3
Explain Adrenergic creation
Tyrosine is shuttled into the cytoplasm (by Na+ dependent tyrosine transporter) and is converted to Dopamine
dopamine is transported into the vesicle via vesicular monoamine transporter 2 (VMAT2) –> converted to NE and upon action potential ca rushes in.
membrane fusion, NE spills out and it activates alpha and beta receptors
there are transporters that serve to reuptake all catecholamines (NE transporter (NET) or Dopamine transporter (DAT))
difference between cholinergic and adrenergic for the process of creation?
reuptake of NE/ EPi into the cytoplasm vs. ACh which is just destroyed
how do you get from tyrosine to epinephrine in the catecholamine synthesis?
to note about NE –> Epi?
where does each occur?
Tyrosine –> Dopa –> Dopamine (occurs in nerve cytoplasm)
Dopamine –> Norepinephrine –> Epinephrine (this occurs in the vesicle)
NE to Epi occurs MAINLY in the adrenal medulla
Why is VMAT2 called promiscuous?
it doesn’t shuttle just dopamine into the cell.. also NE, Epi, and serotonin into the vesicle too!
what does reserpine do?
cocaine?
VMAT2 blocker
block NE transporter
how is catecholamine terminated? (2 ways)
mostly reuptake.
can be metabolized though by 2 enzymes MAO or COMT
What’s to know about Alpha and beta receptors?
what kinds are they?
part of adrenergic signaling
main types are alpha and beta
they’re all GPCRs
Alpha has a1 or a2
beta has b1, b2, or b3
dopamine has 5 types (d1-d5)
Alpha 1 vs Alpha 2?
G protein type?
agonists do they prefer?
Gq –> respond equally to Epi and NE
Gi,Go –> respond equally to epi and NE
B1 vs B2 vs B3?
G protein type?
What agonists do they prefer
all coupled to Gs (activation of this activates adenylyl cyclase to increase cAMP in the cell!)
B1 equal NE or Epi
B2 LOVE Epi over NE
B3 favor NE over Epi
What is the rules of thumb to know about Alpha 1?
Beta 2?
Muscarinic receptors?
it doesn’t matter where they’re located.. they stimulate contraction of smooth muscle. if that smooth muscle surrounds the vasculature, it’ll cause vasoconstriction
Relax smooth muscle - vasodilation if that smooth muscle was surrounding the vasculature.
contract smooth muscle.. doesn’t matter what location in the body. different signal than alpha 1!!
if we block alpha 1, what do we have?
smooth muscle relaxation… if smooth muscle surrounds the vasculature, it’ll be vasodilation
B1 receptor activation on the heart? is this PNS or SNS?
M2 receptors causes what? PNS or SNS?
A1 on blood vessels? what about for parasympathetics?
increase heart rate, increase contractility.. SNS because adrenergic
decrease in heart rate, decrease contractility… PNS because cholinergic
constriction.. but nothing for PNS, this is indirectly through Nitric oxide via M3!!
What does M3 do for the endothelium and blood vessels?
it creates NO by activating NO synthase… this then goes to the blood vessels and vasodilator
What is EDRF?
what did it lead to the discovery of and how does it work?
endothelium derived relaxing factor.. this was allowing the vasculature to dilate in response to acetylcholine.
this occurs only in the presence of intact endothelial cells
acetylcholine activates muscarinic, which increases calcium levels, which results in the production of nitric oxide.
at the time they didn’t know what NO was so they called it EDRF.
NO then diffuses back to smooth muscle to relax.
how do you achieve relaxation and balance of PNS and SNS for smooth muscle and blood vessels?
intact endothelium
baroreceptor reflex?
phenylephrine or histamine examples?
a1 receptor agonists causes constriction or smooth muscle contraction..
this would increase BP in response to this.. it’s sensed by the baroreceptor which then would increase the PNS tone and decrease SNS tone.
if we give histamine (decreases BP), that decrease will be sensed by baroreceptor, which decreases PNS and increases SNS
in general, what do the adrenergic alpha and beta receptors stimulate in the stomach, intestine, motility and tone of the sphincters, and secretion?
what deals with motility?
sphincters?
Secretion?
For the opposite in the PNS, know that M3 and M2 pretty much work equally.
SNS so…
decrease motility, increase contraction of sphincters, and inhibit secretion
alpha 1, alpha 2, b1, b2
A1
Alpha 2
SNS or PNS for renin secretion from the kidney?
NO PNS
only alpha 1 and b1..
alpha 1 decreases secretion, beta 1 increases secretion
What elicits contraction of pilomotor muscles and secretion of sweat?
alpha 1
What elicits K+ and water secretion from salivary glands?
interesting thing?
alpha 1 a little bit from SNS
M3 AND M2 FROM PNS BUT WAY MORE!!
usually SNS and PNS oppose each other, but this one does both, but PNS is just stronger
