Cholinergic pharmacology Flashcards
What is tubocurarine?
Competitive inhibitor of nAChR acts in autonomic ganglia, adrenal medulla
non-depolarising
Reduces the number of available receptors, decreases amplitude of postsynaptic current at NMJ.
Are blood vessels innervated?
No
What is the physiological effect of muscarinic activation in smooth muscle?
Contraction
What is the physiological effect of muscarinic activation in glands?
Secretion
What is the physiological effect of muscarinic activation in the heart?
Relaxation - slow rate and conduction
Which muscarinic agonists are resistant to AChE?
Bethanechol, pilocarpine, muscarine
What are some effects of atropine?
Motion sickness - antiemetic Reduced Parkinsons tremor Cognitive impairment (elderly) Pupil dilation - mydriasis Paralysis of accommodation Reduced secretions Relaxed smooth muscle (bronchi, GIT) Increased heart rate Urinary retention
Why do muscarinic agonists such as pilocarpine help treat glaucoma?
Miosis (pupil constriction) and ciliary spasm improve drainage of aqueous humour reducing intraocular pressure.
Which parts of the heart are innervated by the PSNS?
Sino-atrial and atrio-ventricular
Atria
Which drug can relieve dry mouth?
Pilocarpine
Muscarinic agonist
Which effects are produced by low levels of ACh?
Muscarinic effects
Which drug can affect uptake of choline?
Hemicholinium
Which drug can affect ACh packaging?
Vesamicol
Which drug can affect ACh release?
Botulinum /botox
What are the effects of hexamethonium?
Secretions reduced Vasodilation Tachycardia Constipation Impotence
What is suxamethonium?
Agonist of muscle nicotinic receptors. It is resistant to local esterase.
First, suxamethonium causes depolarisation and AP, but continuing depolarisation causes inactivation so APs blocked.
What are the uses of cholinesterase inhibitors?
Short acting eg edrophonium - diagnose myasthenia gravis
Medium acting eg pyridostigmine eserine - treat myasthenia gravis
Long acting eg ecothiopate -
Can treat glaucoma. Nerve gas, insecticides.
Where can both muscarinic and nicotinic receptors be found?
Autonomic ganglia, adrenal medulla
What are the effects of high doses of atropine?
Stimulation, restlessness, hallucinations, disorientation.
At low doses can result in attention and memory deficits in elderly
