07 Autonomics

Question 1

Autonomic NS anatomical divisions

Answer 1

Sympathetic throacolumbar

Parasympathetic craniosacral

Question 2

PLANSMA

Answer 2

PANS
Long pre-ganglionic fibers
Ach
Nicotinic
Short post-ganglionic fibers
Muscarinic
Acetylcholine

Question 3

Preganglionic fibers

Answer 3

Release Ach, receptor: nicotinic
SANS: adrenergic a/b (muscle) muscarinic (sweat glands)
PANS: muscarinic

Question 4

Somatic NS

Answer 4

Always nicotinic (no ganglia)
Receptor: ion channel -> depolarization

Question 5

Plexuses of ENS

Answer 5

Myenteric (auerbach) = motor activities

Submucosal (meissner) = secretory

Question 6

Neurotransmitters

Answer 6

Ach = nicotinic and muscarinic
NE = adrenergic
Serotonin (5-HT, ENS)

Question 7

ANS receptors

Answer 7

Cholinergic: Muscarinic (M1-3) Nicotinic (Nn = nerves, Nm = muscle)
Adrenergic/noradrenergic (A1, A2, B1, B2, B3)

Question 8

Cholinergic fibers

Answer 8

All preganglionic efferent autonomic fibers
Somatic motor fibers to skeletal muscles
Most PANS postganglionic, some SANS postg

Question 9

Adrenergic fibers

Answer 9

Most SANS postg

Question 10

(cholinergic transmission) Synthesis

Answer 10

Choline Acetyltransferase (cytoplasm: acetyl coa [mt] + choline)
Choline transporter: rate limiting step
Inhibitor: Hemicholinium (blocks CHT symporter)

Question 11

(cholinergic transmission) Storage

Answer 11

VAT: Ach cytoplasm -> vesicles (via proton efflux)
VPG: vesicular proteoglycan bound to vesicular Ach
Inhibitor: Vesamicol (iVAT)

Question 12

(cholinergic transmission) Release

Answer 12

SNARE proteins
VAMPs (align vesicles): vSNARES close to vesicle (synaptobrevin, synaptotagmin)
SNAPS: t-SNARES close to membrane (syntaxin, SNAP25)
Inhibitor: botulinum toxin (blocks vesicle release)

Question 13

(cholinergic transmission) Receptor effects correlates

Answer 13

Cholinometrics/cholinergics: direct acting and indirect acting (stimulates PANS)
Anticholinergics: antimuscarinic, antinicotinics (blocks ach receptor)

Question 14

(cholinergic transmission) Termination of action

Answer 14

AChE: acetate-Ache -> active ache; break down ach, choline is reuptaked
Inhibitors: indirect cholinergics (inhibits ach destruction)

Question 15

(adrenergic transmission) synthesis

Answer 15

Tyrosine hydroxylase (Tyr -> dopa -> NE/E)
Inhibitor: Metyrosine

Question 16

(adrenergic transmission) storage

Answer 16

VMAT: antiporter on vesicle
Inhibitor: Reserpine (depletes transmitter stores)

Question 17

(adrenergic transmission) release

Answer 17

Sympathomimetic drugs: release transmitter from vesicles

Inhibitors: Bretylium, Guanethidine (both used for hypertension, G for glaucoma), amphetamine (inhibit MAO)

Question 18

(adrenergic transmission) receptor effects

Answer 18

Adrenoreceptors: a1, a2, b1/2/3 (targeted by salbutamol and beta blockers), dopamine receptors
Inhibitors: adrenergic receptor agonists and antagonists

Question 19

(adrenergic transmission) termination of action

Answer 19

Diffusion/reuptake, destroyed by MAO/COMT
NET (uptake 1): carries NE into cytoplasm
Inhibitor: cocaine, tricyclic antidepressants

Question 20

5HTm

Answer 20

Receptor for locomotion and vasoconstriction
Sumatriptan (for migraine): binds to 5HTm -> vasoconstriction of brain vasculature
Yohimbine (for erectile dysfunction, increasing libido)

Question 21

5HT3

Answer 21

Stimulates vomiting (5HT3 receptors on vagal afferents & central receptors)
Anti-emetics: Ondansetron, metoclopramide (motion sickness)

Question 22

Integration of CVS function

Answer 22

SANS (increase): peripheral vascular resistance, heart rate, contractile force, venous tone
PANS: decrease HR
Angiotensin II (increase): peripheral vascular resistance, SANS effects
Aldosterone: increase BV

Question 23

PANS and eye

Answer 23

PANS = constriction of the eye
Organophosphate poisoning = too much constriction
Atropine (anti-cholinergic): PANS inhibitor = blocks eye constriction, cannot be used on pts with glaucoma

Question 24

Drugs for glaucoma

Answer 24

a-receptor agonism: decrease aqueous production

B-receptor antagonism: inhibits increase of aqueous production