Cholinergic Pharmacology Flashcards
Effect of a direct-acting Cholinergic agonist in the CNS
- doesn’t cross the blood brain barrier
Effect of a direct-acting Cholinergic Agonist on the Cardiovascular system
- vasodilation
- decrease intropy and chronotropy
Effects of a direct-acting Cholinergic Agonist on the Respiratory System
- bronchoconstriction
- increased secretion
Effects of direct-acting Cholinergic Agonist on the GI System
- increased motility and secretion
Effects of direct-acting Cholinergic Agonists on the Urinary system
- potential increase in voiding pressure
Effects of direct-acting Cholinergic Agonist on the Glands
- sweating
- salivation
Carbachol (drug type)
- activates both nicotinic and muscarinic receptors
- ACh analogue that is resistant to cholinesterases - have a longer half life
- direct-acting cholinergic drug
Carbachol uses
- open angle glaucoma
Muscarinic Receptor Selective Direct Acting Cholergic Agonist
- Bethanechol
- Pilocarpine
- Cevimeline
Bethanechol Pharmacology
- resistant to cholineresterases -> longer action
- acts predominantly at muscarinic receptors
- primarily affects GI and urinary tracts (orally)
Bethanechol Uses
- urinary retention
- gastroesophageal Reflux
Pilocarpine Pharmacology
- naturally occuring alkaloid
- longer acting than ACh
- predominantly muscarinic action
Pilocarpine Uses
- open angle glaucoma
- Xerostomia (dry mouth)
Muscarinic Receptor Subtypes
M1, M2, M3, M4, M5
Stimulatory Muscarinic Receptor Subtypes
- M1, M3, M5
- post-synaptic
Inhibitory Muscarinic Receptor Subtypes
- M2, M4
- pre-synaptic
M1 is located in:
- Parasympathetic ganglia
- Salivary Gland
- Stomach
Activation of M1 in the Parasympathetic ganglia causes:
- increased parasympathetic tone
Activation of M1 in the Salivary gland causes:
- increased saliva
Activation of M1 in the Stomach causes:
- acid release
M2 is located in:
- Heart
- GI smooth muscle
- Bladder smooth muscle
- CNS
Activation of M2 in the heart causes:
- decrease heart rate
- decrease force of contraction
Activation of M2 in the GI smooth muscle causes:
- opposes sympathetically-mediated relaxation
Activation of M2 in the Bladder smooth muscle causes:
- opposes sympathetically- mediated relaxation
Activation of M2 in the CNS causes:
- analgesia - maybe
M3 is located in:
- Bladder Smooth muscle
- Airway smooth muscle
- GI smooth muscle
- Eye
- Glands
- Blood vessels
Activation of M3 in the Bladder smooth muscle causes:
- contraction of the bladder for micturation
Activation of M3 in the Airway smooth muscle causes:
- bronchoconstriction
Activation of M3 in the GI smooth muscle causes:
- contraction
Activation of M3 in the Eye causes:
- constriction of pupil
- contraction of ciliary muscle
- contraction of trabecular meshwork
Activation of M3 in the Glands causes:
- salivation
Activation of M3 in the Blood Vessels causes:
- dilation (through the endothelium release of NO)
M4 is located in:
- prejunctional nerve endings
- CNS
Activation of M4 in the prejunctional nerve endings caues:
- inhibition of ANS transmittion
Activation of M4 in the CNS causes:
- Schizoprenia or Analgesia - maybe?
M5 is found in:
CNS
Activation of M5 in the CNS causes:
- facilitates dopamine releases
- regulates cerebral vascular tone by causing vascular dilation
Cevimeline Pharmacology
- activates M1 and M3 receptors - prevalent in salivary glands
- 40 fold relative affinity for M3 than M2 for the cardiac receptor compared to pilocarpine
Cevimeline Uses
- Sjorgen’s Syndrome
Nicotine Pharmacology
- natural alkaloid
- activates both neuronal (ganglion and CNS) and skeletal muscle nicotinic receptors - greater affinity for neuronal receptors
- activates both parasympathetic and sympathetic ganglian
Nicotine Effects on the CNS
- marked stimulation - realses glutamate, dopamine etc..
- high doses cause tremor and can lead to convulsions
- stimulates the chemoreceptors trigger zone (nausea)
Nicotine effects on the Cardiovascular System
- hypertension
- tachycardia
(stimulates sympathetic ganglion)
Nicotien effects on the Respiratory System
- bronchoconstriction
- increased secretions
Nicotine effects on the GI system:
- Nausea
- Vomitting
- increased bowel motility (diarrhea)
Nicotine effects on the Urinary System
- potential increase in voiding pressure (usually not observed)
Nicotine effects on the Glands:
- initial salivary and bronchial secretion
- then inhibition
Nicotine effects on the Peripheral Nervous System
- transient stimulation followed by a more prolonged desensitization of the autonomic ganglia and skeletal muscles
Nicotine Uses
- smoking cessation
Nicotinic Receptor Agonists
- nicotine
- Varenicline
Varenicline Pharmacology
- partial agnosit/antagonist highly selective for alpha4beta2 nicotinic ACh receptor
- inhibits nicotine-induced dopaminergic reward pathway activation
- decreases the reinforming effect of smoking bymaking it less rewarding
Varenicline Uses
- smoking cessation
Varenicline Adverse Effects
- mild to moderate nausea reported
- insomnia and abnormal dreams
- neuropsychiatric adverse events
Indirect-Acting Cholinergic Agonists MOA:
- cholinesterase inhibitors which block the break down of ACh at
1. Neuromuscular synapse
2. Autonomic ganglion synapses
3. parasympathetic effector synapses
Edrophonium Pharmacology
- reverses paralysis of non-depolarizing neuromuscluar blockers
- Cholinesterase inhibitor (aka indirect-acting cholinergic agonist)
Edrophonium Uses
- myasthenia gravis diagnostic event
Neostigmine Pharmacology
- cholinesterase inhibitor (aka indirect-acting cholinergic agonist)
Neostigmine Uses
- postoperative ileus
- postoperative urinary retention