WGU D116 UNIT 3 NOTES
Unit 3 Ch 12&18 p. 28-30
Analyzing Neuropharmacology
Vocabulary
Central Nervous System (CNS)- brain and spinal cord
Peripheral Nervous System (PNS)- 2 major subdivisions
1. Somatic nervous system- controls voluntary movement
2. Autonomic nervous system- involuntary processes s/a regulation of
heart, secretory glands, regulation of smooth muscle
Further subdivisions:
1. sympathetic system
2. parasympathetic system
MOA (Mechanism of Action)
Drug tolerance Physical dependence
CNS Pharmacology
Feedback regulation- a process that allows a system to adjust itself by
responding to incoming information
* Stimulation of sympathetic nerves to the heart increases cardiac output.
* Release of epinephrine from the adrenal medulla results in
vasoconstriction
*The PNS employs three neurotransmitters: acetylcholine, norepinephrine,
and epinephrine. Any given junction in the PNS uses only one of these
transmitter substances
1. Identify the categories of neurotransmitters in the CNS.
-monoamines (dopamine, serotonin, epinephrine, norepinephrine)
-amino acids (asparate, glycine, glutamate)
-purines (adenosine)
-opioid peptides (endorphins)
-nonopioid peptides (oxytocin, vasopressin)
-other (acetylcholine, histamine)
2. Identify the responses of skeletal and ciliary muscles to CNS drug classes
(table 12.1)
Skeletal muscle responses depend on motor neuron activity and NMJ
transmission—CNS drugs can either suppress (muscle relaxants,
benzodiazepines) or enhance (stimulants, cholinesterase inhibitors) motor
output.
,Ciliary muscle responses are almost entirely parasympathetic (muscarinic)
and affected by drugs that modify cholinergic signaling.
3. Discuss the implication of the long-term use of CNS drugs as it pertains
to therapeutic effects and side effects.
-increased therapeutic effects
-decreased side effects
-tolerance and physical dependence
4. Summarize the function of cholinergic receptor subtypes (table 12.2).
Receptor: α₁
Location: Vascular smooth muscle, iris radial muscle, bladder
sphincter
Action: Vasoconstriction ↑ BP, mydriasis (pupil dilation), urinary retention
Receptor: α₂
Location: Presynaptic nerve terminals, platelets, some vascular smooth
muscle
Action: ↓ NE release (negative feedback), ↓ sympathetic outflow, platelet
aggregation
Receptor: β₁
Location: Heart (SA node, AV node, myocardium), kidney (juxtaglomerular
cells)
Action: ↑ HR (chronotropy), ↑ contractility (inotropy), ↑ conduction velocity
(dromotropy), ↑ renin release
Receptor: β₂
Location: Bronchial smooth muscle, vascular smooth muscle (skeletal
muscle beds), uterus, liver
Action: Bronchodilation, vasodilation in skeletal muscle, uterine relaxation,
↑ glycogenolysis/gluconeogenesis
Receptor: β₃
Location: Adipose tissue, bladder
Action: ↑ Lipolysis, bladder detrusor relaxation
5. Summarize the function of peripheral adrenergic receptor subtypes (table
12.3).
-cholinergic receptors- receptors that mediate responses to Ach
, -adrenergic receptors- receptors that mediate responses to
epinephrine (adrenaline) and norepinephrine (noradrenaline)
6. Discuss the life cycle of acetylcholine, norepinephrine and epinephrine
ACh works fast at synapses and is broken down by enzymes, NE acts at
nerve endings and is taken back up, and Epi is a hormone released into the
blood for whole-body effects.
Cholinergic Agents
-Muscarinic Agonists- BETHANECHOL
-Cholinesterase Inhibitors- PYRIDOSTIGMINE
-Muscarinic Antagonists- ATROPINE
MUSCARINIC AGONISTS
* Muscarinic agonists are drugs that stimulate muscarinic acetylcholine
receptors (mAChRs), mimicking the effects of the parasympathetic nervous
system (“rest and digest”)
MOA- mimic the action of acetylcholine (ACh) by binding to and activating
muscarinic acetylcholine receptors (mAChRs).
Pharmacologic effects- miosis, decreased IOP, decreased HR and
contractility, bronchoconstriction, increased bronchial secretions, increased
GI motility and tone, sphincter relaxation, ↑ Sweating, salivation,
lacrimation, and other exocrine secretions
Therapeutic uses-
Post-op or neurogenic urinary retention, atonic bladder
Muscarinic (Cholinergic) Toxicity DUMBELS
Diaphoresis/Diarrhea
Urination
Miosis
Bradycardia/Bronchospasm/bronchorrhea
Emesis
Lacrimation
Salivation
CHOLINESTERASE INHIBITORS
PYRIDOSTIGMINE
-drug of choice for MG or Atropine OD
Monitor HR, BP, and myasthenic crisis
Contraindicated with mechanical obstruction of the intestine or urinary
tract
, Caution in patients with peptic ulcer disease, bradycardia, asthma, or
hyperthyroidism
Assess for increased strength and muscle control
MUSCARINIC ANTAGONIST
8. Identify the special considerations across the lifespan for muscarinic
agonists.
Neonates- immature organs, altered metabolism and excretion, heightened
sensitivity, increase risk CNS effects due to increased BBB permeability
Children- GI side effects, bronchospasm, weight based drugs,
TX: Admin Atropine (a selective muscarinic blocking agent)
9. Summarize the key prescribing considerations for Bethanechol.
-contraindicated in patients with PUD, urinary tract obstruction, intestinal
obstruction, coronary insufficiency, hypotension, asthma, and
hyperthyroidism
11. Differentiate between the reversible and irreversible cholinesterase
inhibitors.
Reversible = temporary, therapeutic use.
Irreversible = permanent, mostly toxic.
12. Discuss the special considerations across the lifespan for cholinesterase
inhibitors.
Older adults= primary population TX Alzheimer’s disease
- Heightened sensitivity to cholinergic adverse effects (syncope,
bradycardia, GI upset, weight loss).
- Fall risk increases due to dizziness, syncope, or hypotension
Unit 3 Ch 12&18 p. 28-30
Analyzing Neuropharmacology
Vocabulary
Central Nervous System (CNS)- brain and spinal cord
Peripheral Nervous System (PNS)- 2 major subdivisions
1. Somatic nervous system- controls voluntary movement
2. Autonomic nervous system- involuntary processes s/a regulation of
heart, secretory glands, regulation of smooth muscle
Further subdivisions:
1. sympathetic system
2. parasympathetic system
MOA (Mechanism of Action)
Drug tolerance Physical dependence
CNS Pharmacology
Feedback regulation- a process that allows a system to adjust itself by
responding to incoming information
* Stimulation of sympathetic nerves to the heart increases cardiac output.
* Release of epinephrine from the adrenal medulla results in
vasoconstriction
*The PNS employs three neurotransmitters: acetylcholine, norepinephrine,
and epinephrine. Any given junction in the PNS uses only one of these
transmitter substances
1. Identify the categories of neurotransmitters in the CNS.
-monoamines (dopamine, serotonin, epinephrine, norepinephrine)
-amino acids (asparate, glycine, glutamate)
-purines (adenosine)
-opioid peptides (endorphins)
-nonopioid peptides (oxytocin, vasopressin)
-other (acetylcholine, histamine)
2. Identify the responses of skeletal and ciliary muscles to CNS drug classes
(table 12.1)
Skeletal muscle responses depend on motor neuron activity and NMJ
transmission—CNS drugs can either suppress (muscle relaxants,
benzodiazepines) or enhance (stimulants, cholinesterase inhibitors) motor
output.
,Ciliary muscle responses are almost entirely parasympathetic (muscarinic)
and affected by drugs that modify cholinergic signaling.
3. Discuss the implication of the long-term use of CNS drugs as it pertains
to therapeutic effects and side effects.
-increased therapeutic effects
-decreased side effects
-tolerance and physical dependence
4. Summarize the function of cholinergic receptor subtypes (table 12.2).
Receptor: α₁
Location: Vascular smooth muscle, iris radial muscle, bladder
sphincter
Action: Vasoconstriction ↑ BP, mydriasis (pupil dilation), urinary retention
Receptor: α₂
Location: Presynaptic nerve terminals, platelets, some vascular smooth
muscle
Action: ↓ NE release (negative feedback), ↓ sympathetic outflow, platelet
aggregation
Receptor: β₁
Location: Heart (SA node, AV node, myocardium), kidney (juxtaglomerular
cells)
Action: ↑ HR (chronotropy), ↑ contractility (inotropy), ↑ conduction velocity
(dromotropy), ↑ renin release
Receptor: β₂
Location: Bronchial smooth muscle, vascular smooth muscle (skeletal
muscle beds), uterus, liver
Action: Bronchodilation, vasodilation in skeletal muscle, uterine relaxation,
↑ glycogenolysis/gluconeogenesis
Receptor: β₃
Location: Adipose tissue, bladder
Action: ↑ Lipolysis, bladder detrusor relaxation
5. Summarize the function of peripheral adrenergic receptor subtypes (table
12.3).
-cholinergic receptors- receptors that mediate responses to Ach
, -adrenergic receptors- receptors that mediate responses to
epinephrine (adrenaline) and norepinephrine (noradrenaline)
6. Discuss the life cycle of acetylcholine, norepinephrine and epinephrine
ACh works fast at synapses and is broken down by enzymes, NE acts at
nerve endings and is taken back up, and Epi is a hormone released into the
blood for whole-body effects.
Cholinergic Agents
-Muscarinic Agonists- BETHANECHOL
-Cholinesterase Inhibitors- PYRIDOSTIGMINE
-Muscarinic Antagonists- ATROPINE
MUSCARINIC AGONISTS
* Muscarinic agonists are drugs that stimulate muscarinic acetylcholine
receptors (mAChRs), mimicking the effects of the parasympathetic nervous
system (“rest and digest”)
MOA- mimic the action of acetylcholine (ACh) by binding to and activating
muscarinic acetylcholine receptors (mAChRs).
Pharmacologic effects- miosis, decreased IOP, decreased HR and
contractility, bronchoconstriction, increased bronchial secretions, increased
GI motility and tone, sphincter relaxation, ↑ Sweating, salivation,
lacrimation, and other exocrine secretions
Therapeutic uses-
Post-op or neurogenic urinary retention, atonic bladder
Muscarinic (Cholinergic) Toxicity DUMBELS
Diaphoresis/Diarrhea
Urination
Miosis
Bradycardia/Bronchospasm/bronchorrhea
Emesis
Lacrimation
Salivation
CHOLINESTERASE INHIBITORS
PYRIDOSTIGMINE
-drug of choice for MG or Atropine OD
Monitor HR, BP, and myasthenic crisis
Contraindicated with mechanical obstruction of the intestine or urinary
tract
, Caution in patients with peptic ulcer disease, bradycardia, asthma, or
hyperthyroidism
Assess for increased strength and muscle control
MUSCARINIC ANTAGONIST
8. Identify the special considerations across the lifespan for muscarinic
agonists.
Neonates- immature organs, altered metabolism and excretion, heightened
sensitivity, increase risk CNS effects due to increased BBB permeability
Children- GI side effects, bronchospasm, weight based drugs,
TX: Admin Atropine (a selective muscarinic blocking agent)
9. Summarize the key prescribing considerations for Bethanechol.
-contraindicated in patients with PUD, urinary tract obstruction, intestinal
obstruction, coronary insufficiency, hypotension, asthma, and
hyperthyroidism
11. Differentiate between the reversible and irreversible cholinesterase
inhibitors.
Reversible = temporary, therapeutic use.
Irreversible = permanent, mostly toxic.
12. Discuss the special considerations across the lifespan for cholinesterase
inhibitors.
Older adults= primary population TX Alzheimer’s disease
- Heightened sensitivity to cholinergic adverse effects (syncope,
bradycardia, GI upset, weight loss).
- Fall risk increases due to dizziness, syncope, or hypotension
