06 - Autonomic, 07 - Cholinoreceptor-activating and cholinesterase inhibiting drugs Flashcards
Spinal roots of origin SANS
Thoracic T1-12
Lumbar L1-5
segments of SC
Spinal roots of origin PANS
CN III, VII, IX, and X
sacral segments of spinal cord
Location of ganglia SANS
paravertebral chains that lie along the spinal column, some along the anterior aspect of the abdominal aorta
Location of ganglia PANS
most are located in the organs innervated, more distant from the spinal cord
Preganglionic fibers SANS
short
Preganglionic fibers PANS
long
postganglioni fibers SANS
long
postganglioni fibers PANS
short
Pupils sympathetic effect/receptor
parasympathetic effect/receptor
mydriasis a1
miosis m3
Heart rate sympathetic effect/receptor
parasympathetic effect/receptor
tachycardia B1
bradycardia M2
Heart contractility sympathetic effect/receptor
parasympathetic effect/receptor
increased b1
decreased m1
Blood vessels skin, splanchnic sympathetic effect/receptor
parasympathetic effect/receptor
constriction a1
no effect
Blood vessels skeletal sympathetic effect/receptor
parasympathetic effect/receptor
dilation b2, m3
no effect
bronchi sympathetic effect/receptor
parasympathetic effect/receptor
dilation b2
constriction m3
GIT walls sympathetic effect/receptor
parasympathetic effect/receptor
relaxation a2, b2
contraction m3
GIT spincters sympathetic effect/receptor
parasympathetic effect/receptor
contraction a1
relaxation m3
GIT secretion sympathetic effect/receptor
parasympathetic effect/receptor
no effect
increased m1, m3
bladder wall sympathetic effect/receptor
parasympathetic effect/receptor
relaxation b2
contraction m3
bladder sphincter sympathetic effect/receptor
parasympathetic effect/receptor
contraction a1
relaxation m3
uterus sympathetic effect/receptor
parasympathetic effect/receptor
contraction a1, relaxation b2
contraction m3
penis sympathetic effect/receptor
parasympathetic effect/receptor
ejaculation a
erection m
sweat glands sympathetic effect/receptor
parasympathetic effect/receptor
increased sweating a
no effect
liver sympathetic effect/receptor
parasympathetic effect/receptor
gluconeogenesis, glycogenolysis a,b2
no effect
fat cells sympathetic effect/receptor
parasympathetic effect/receptor
lipolysis b3
no effect
kidney sympathetic effect/receptor
parasympathetic effect/receptor
increased renin b1
no effect
PLASMA mnemonic
for parasympathetic nervous system P-NS L-ong preganglionic fibers A-cetylcholine S-hort postganglionic fibers A-cetylcholine
Point and shoot mnemonic
point (erection) = PNS
shoot (ejaculation) = SNS
primary transmitter in all autonomic ganglia and at the synapses between parasympathetic postganglionic neurons and their effector cells
primary transmitter at the somatic (voluntary) skeletal muscle neuromuscular junction
acetylcholine
ACh is synthesized from acetyl CoA and choline by
ChAT
choline acetyltransferase
choline transport is inhibited by
hemicholinium
ACh is actively transported into vesicles for storage by
VAT
vesicle associated transporter
VAT is inhibited by
vesamicol
entry of calcium triggers interaction among
SNARE proteins
VAMPs and SNAPs
toxin that alters synaptobrevins to prevent release of ACh
botulinum
degradation of ACh into choline and acetate by
acetylcholinesterase
degradation of ACh is inhibited by
inderect actin cholinomimetics
neostigmine, carbamates, and organophosphates
Cholinomimetic drug types
direct acting
- muscarinic (choline esters, alkaloids)
- nicotinic
indirect
- edrophonium (short acting)
- carbamates (intermediate to long)
- organophosphates (very long)
BETANECHOL class similar drug MOA uses SE
- cholinomimetic (direct-acting, muscarinic)
- carbachol (act on both M and N receptors)
- activates muscarinic M1-M3 receptors (act on M receptors only)
- bladder and bowel atony (post-surgery or spinal cord injury)
- cyclospasm, diarrhea, urinary urgency, vasodilation, reflex tachycardia, sweating
PILOCARPINE class similar drug MOA uses SE
- cholinomimetic (direct-acting, muscarinic)
- cevimeline (m3 selective)
- activates muscarinic M3 receptors in ciliary muscle (increasing aqueous humor outflow) and salivary glands (increasing salivation)
- glaucoma, sjorgren syndrome, sicca syndrome
- miosis, blurring of vision (due to cyclospasm)
Sjogren syndrome triad
xerostomia (dry mouth)
xerophthalmia (dry eyes)
RA
NICOTINE class similar drug MOA uses SE
- cholinomimetic (direct-acting, nicotinic)
- varenicline
- activates nicotinic Ach receptors (Nn and Nm)
- smoking cessation
- generalized ganglionic stimulation (hypertension, tachycardia, nausea, vomiting, diarrhea)
overdose leads to convulsions, paralysis, and coma
Muscarinic toxicity CNS stimulation or depression?
stimulation
Muscarinic toxicity eye
miosis, spasm of accomodation
Muscarinic toxicity lungs
bronchoconstriction
Muscarinic toxicity GIT/GUT
excessive GI and genitourinary smooth muscle activity
Muscarinic toxicity increased secretory activity in
sweat glands
airway
GI tract
lacrimal glands
Muscarinic toxicity blood vessels
vasodilation
Nicotinic toxicity ganglionic stimulation or depression?
stimulation
Nicotinic toxicity blockade of
neuromuscular end plate depolarization leading to fasciculations and paralysis
Nicotinic toxicity CNS stimulation or depression?
CNS stimulations (convulsions) followed by CNS depression
MOA of indirect-acting cholinomimetics
- bind to cholinesterase and undergo prompt hydrolysis
- alcohol portion released, acidic portion retained and released slowly
- – prevents binding and hydrolysis of endogenous ach
- – amplify ach effects wherever ach is released
- no significant actions at uninnervated sites where ach is not normally released
EDROPHONIUM class similar drug MOA uses SE
- cholinomimetic (indirect) [alcohol]
- none
- inhibits acetylcholinesterase, amplifies endogenously released ach
- myasthenia gravis (tensilon test)
- miosis, salivation, nausea, vomiting, diarrhea
very short acting upon IV administration
EDROPHONIUM
tensilon test
for differentiation of cholinergic crisis and myasthenic crisis
improves muscle strength in myasthenic crisis
weakens muscle strength in cholinergic crisis
NEOSTIGMINE class similar drug MOA uses SE
- cholinomimetic (indirect)
- pyridostigmine, physostigmine, ambenonium, demecarium (carbamates), echothiophate (organophosphate)
- inhibits acetylcholinesterase, amplifies endogenously released ach
- myasthenia gravis treatment, reversal of nondepolarizing neuromuscular blockade, glaucoma (physostigmine, echothiophate, demecarium)
- miosis, salivation, nausea, vomiting, diarrhea, bradycardia
NEOSTIGMINE
muscarinic effects are blocked by
atropine
Other organophosphates:
insecticides
malathion
parathion
Other organophosphates:
nerve gases
sarin
tabun
soman
myasthenia gravis
autoimmune destruction of nicotinic ach receptors characterized by: - fluctuating muscle - weakness - ocular symptoms - bulbar symptoms - proximal muscle weakness
differentiate myasthenic crisis from cholinergic crisis
myaesthenic crisis - acute worsening of symptoms due to infection, stress, or undermedication
cholinergic crisis - excessive activation of cholinoreceptors (skeletal muscle weakness and parasymapthetic signs) due to overmedication
RIVASTIGMINE class similar drug MOA uses SE
- cholinomimetic (indirect)
- galantamine, donepezil, tacrine
- inhibits acetylcholinesterase, amplifies endogenously released acetylcholine
- alzheimer’s disease
- miosis, salivation, nausea, vomiting, diarrhea, bradycardia
organophosphate poisoning signs and symptoms
DUMBBELSS
diarrhea urination miosis bronchospasm bradycardia excitation (skeletal muscle and CNS) lacrimation sweating salivation
treatment of organophosphate poisoning
atropine
pralidoxime
ATROPINE class similar drug MOA uses SE
- cholinergic antagonist (muscarinic)
- blah
- competitively blocks all muscarinic receptors
- mydriatic, cyclopegic, antidote for organophosphate poisoning (first choice), bradycardia, hypersalivation, decrease airway secretion during general anesthesia
- tachycardia, mydriasis, cyclopegia, skin flushing, delirium, hallucinations, urinary retention, constipation
no effect on nicotinic signs of toxicity; notorious for causing hyperthermia
PRALIDOXIME class similar drug MOA uses SE
- cholinesterase regenerator, antidote
- blah
- binds phosphorus of organophosphate, breaks organophosphate bond with cholinesterase
- antidote for organophosphate poisoning and nerve gas poisoning (sarin, tabun)
- muscle weakness
- must be administered before 6-8 hours of organophosphate bond with cholinesterase occurs
Cholinoreceptor blocker types
anticholinergic drugs
- antimuscarinic
- –M1-selective (pirenzepine)
- –non-selective (atropine)
- antinicotinic
- –ganglion blockers (hexamethonium)
- –neuromuscular blockers (tubocurarine)
cholinesterase regenerators
- oximes (pralidoxime)