Autonomic Pharmacology Flashcards
-lytic
- Blocking or impairing
- Interfering medications
-mimetic
- Mimicking or enhancing
- Medication that amplifies
Cholinergic Neurotransmitters and Receptors
- Acetylcholine is the NT
- in the ANS:
- All parasympathetic and sympathetic pre-ganglionic fibers
- All parasympathetic post-ganglionic fibers
- Sympathetic post-ganglionic fiber innervated to sweat glands
- Two major classes of receptors for acetylcholine:
- Muscarinic
- Nicotinic
Muscarinic:
Receptor Type
Neurotransmitter
Subtypes
- Receptor Type: G-Protein Coupled Receptors
- Neurotransmitter: Acetylcholine
- Subtypes: M1 through M5
Nicotinic:
Receptor Type
Neurotransmitter
Subtypes
- Receptor Type: Linked to Ion Channels
- Neurotransmitter: Acetylcholine
- Subtypes:
- Muscle-Type on Skeletal Muscle
- Neuronal-Type (will cover more in block 3)
Cholinergic activation causes what symptoms?
- Diarrhea
- Urination
- Miosis (constriction of the pupil)
- Bradycardia
- Bronchoconstriction
- Emesis
- Lacrimation (the flow of tears)
- Salivation
Cholinergic = DUMBBELS
M1 Location
CNS and peripheral nerves
M2
Location
Effect
Location: Heart and presynaptic nerve terminals
Effect:
- Decrease HR and contractility
- Inhibits Ach release
M3
Location
Effect
Location:
- Iris constrictor and ciliary muscle
- Vascular endothelium
- GI muscle, bladder, uterus
- Gastric parietal cells
- Bronchial smooth muscle
- Exocrine glands
Effect:
- Contraction miosis/accommodation
- EDRF release –> vasodilation
- Increase GI motlity and urination
- Acid secretion/digestion
- Bronchoconstriction
- Salivation/Lacrination
M4 Location
CNS neurons
M5
Location
Effect
Location: Vascular endothelium
Effect: Vasodilation
Cholinomimetics
Drugs which produce effects similar to the effects of Acetylcholine
Direct-acting cholinomimetics
Drugs that act as agonists of muscarinic/nicotinic receptors
Three examples of cholinomimetics
Mechanisms of Action
Indication
Bethanechol
- Muscarinic receptor agonist (non-specific)
- Used to treat urinary retention
Pilocarpine
- Muscarinic receptor agonist (non-specific)
- Used to treat glaucoma and Sjogren’s syndrome
Nicotine
- Nicotinic receptor agonist (non-specific)
- Used for smoking cessation
Indirect-acting cholinomimetic
Drugs that produce cholinomimetic effects either by facilitating synthesis/release of Ach or by inhibiting degredation of Ach
Becuase they incre [Ach] they can have effects at (neuromuscular junctions (nicotinic)
Two examples of indirect-acting cholinomimetics
Mechanism of action
Indication
Neostigmine
- Cholinesterase inhibitor (reversible, intermediate-acting)
- Used to treat Myasthenia gravis
Donepezil
- Cholinesterase inhibitor (reversible, intermediate-acting)
- Used to treat Alzheimer’s disease
Cholinolytics definition
Drugs that interfere with or block the action of acetylcholine
Produce opposite effect of cholinomimetics
Cholinolytic general effects
Produce opposite effect of cholinomimetics
Opposite of DUMBBELS:
Constipation (instead of diarrhea)
Urinary retention (instead of urination)
Mydriasis: dialation of pupil (instead of miosis)
Tachycardia (instead of bradycardia)
Bronchodilation (instead of bronchoconstriction)
Decreased GI motility/secretion (instead of emesis)
Dry eyes (instead of lacrimation)
Dry mouth (instead of salivation
Direct-acting cholinolytics
Drugs that are antagonists of muscarinic/nicotinic receptors
Three examples of direct-acting cholinolytics
Mechanisms of action
Indication
Atropine
- Muscarinic receptor antagonist (non-specific)
- Used to treat cardiac arrest, IBS, and organophosphorus poisoning (a pestiside)
Oxybutynin
- Muscarinic receptor antagonist (non-specific)
- Used to treat urinary incontinence
Darifenacin
- Muscarinic receptor antagonist (M3 specific)
- Used to treat urinary incontinence
Indirect-acting cholinolytic
Drugs that produce cholinolytic effects by either inhibiting the synthesis/release of Ach or by promoting the Ach degradation
One example of a indirect-acting cholinolytic
Mechanism of action
Indication
Pralidoxime
- Cholinesterase regenerator
- Used to treat organophosphorus poisoning (a pesticide)
Which adrenergic receptors react to epinephrine?
Why is this significant?
All of them: a1, a2, b1, b2, and b3
This is significant because activation of the sympathetic nervous system leads to the adrenal glands releasing epinephrine into the bloodstream
a1
Location
Effects
Locations:
- Vascular smooth muscle
Effects:
- Vasoconstriction (increases BP)
a2
Location
Effect
Location
- Presynaptic nerve terminals
Effect
- Inhibits norepinephrine release
b1
Location
Effect
Location
- Heart
Effect
- Increases heart rate and force of contraction
b2
Location
Effect
Location
- Bronchial, bladder, and uterine smooth muscle
Effect
- Bronchodilation
- Urinary retention
b3
Location
Effect
Location
- Bladder and adipose tissue
Effect
- Urinary retention
- Lipolysis
Sympathomimetics/Adrenomimetics
Drugs which produce effects similar to the effects of NE/EPI
Direct-acting sympathomimetics
Drugs that are agonists of alpha and beta receptors
Five examples of sympathomimetic drugs
Mechanism of action
Indication
Epinephrine
- Alpha and beta receptor agonist (non-specific)
- Used to treat anaphylactic shock
Phenylephrine
- Alpha-1 receptor agonist (causes vasoconstriction)
- Used to treat nasal congestion
Clonidine
- Alpha-2 receptor agonist (decrease NE release)
- Used to treat hypertension
Dobutamine
- Beta-1 receptor agonist (increase HR and cardiac output)
- Used to treat cardiogenic shock and acute heart failure
Terbutaline
- Beta-2 receptor agonist (relaxes bronchial/tracheal smooth muscle)
- Used to treat asthma
Indirect-acting sympathomimetics
Drugs that produce sympathomimetic effects either by facilitating the synthesis and release of NE or by inhibiting the reuptake/degradation of NE
Two examples of indirect-acting sympathomimetics
Mechanism of action
Indication
Amphetamine
- Facilitate release of NE from sympathetic nerve endings
- Used to treat ADHD
Selegiline
- Inhibits NE/EPI metabolizing enzyme monoamine oxidase (MAO)
- Used to treat the symptoms of Parkinson’s disease
Mixed-action sympathomimetics
Drugs the produce sympathomimetic effects by facilitating the release of NE from nerve endings and acting as adrenoceptor agonists
Two examples of mixed-action sympathomimetics
Mechanism of action
Indication
Ephedrine
- Facilitates NE release (indirect) and activates both alpha and beta receptors (direct)
- Used to treat nasal congestion
Pseudoephedrine
- Facilitates NE release (indirect) and activates both alpha and beta receptors (direct)
- Used to treat nasal congestion
Sympatholytics
Drugs that interfere with or block the actions of NE/EPI
Direct-acting sympatholytics
Drugs that are antagonists of alpha and beta receptors
5 examples of direct-acting sympatholytics
Mechanism of action
Indication
Labetalol
- Blocks all alpha and beta receptors except alpha-2 (non-specific)
- Used to treat hypertension
Phenoxybenzamine
- Alpha blocker, irreversible (non-specific)
- Used to treat pheochromocytoma (rare adrenal gland tumor)
Doxazosin
- Alpha-1 blocker
- Used to treat hypertension and BPH
Propranolol
- Beta blocker (non-specific)
- Used to treat hypertension, angina pectoris, and arrhythmias
Atenolol
- Beta-1 blocker
- Used to treat hypertension, angina pectoris, and arrhythmias
Indirect-acting sympatholytics
Drugs that produce sympatholytic effects either by inhibiting the synthesis or release of NE
These drugs are currently not in clinical use
