cpps 304 autonomic pharmacology parasympathetic

What type of receptor are M2 and M4?

Gai

what type of receptor are M1, M3, M5?

Gq

2 subtypes of nicotinic receptors

Nn and Nm

physostigmine

AChEI

Rivastigmine

reversible AChEI

drugs ending in chol and ine

direct cholinergic agonists

drugs ending in stigmine (plus donepezil)

indirect acting cholinergic agonists

atropine, oxybutynin, scopolamine, ipratropium

antimuscarinic agents

mecamylamine

ganglionic blocker

succinylcholine, atracurium, mivacurium

neuromuscular blockers

pralidoxime

cholinesterase reactivator (decreases ACh)

What receptor is found in GI tract

M3

what do muscarinic agonists do to the GI tract?

contract smooth muscle, increase peristalsis, increase gastric acid secretion

neostigmine

cholinergic agent used to treat GI hypomotility (postoperative ileus)

methyl scopolamine

muscarinic antagonist used as antispasmodics in GI

side effects of cholinergic agents in GI tract

diarrhea, cramping, acidity (so do not use them if you have peptic ulcers)

what receptors are found in salivary glands

M3

pilocarpine and cevimeline

muscarinic agonist used to treat dry mouth

muscarinic stimulation in salivary glands

increases salivary and mucus secretions

what type of receptor is in the bladder

M3

what do muscarinic agonists do to the bladder

contract detrusor (opposite of beta3 in sympathetic)

oxybutynin and darifenacin

muscarinic antagonist used to treat overactive bladder and urinary incontinence

who should not use muscarinic antagonists?

people who experience urinary retention

bethanechol

muscarinic agonist used to treat urinary retention when there is no obstruction, but a loss of muscle tone

what receptor is found in bronchial smooth muscle

M3

what do muscarinic agonists do to bronchial smooth muscle

contract them and increase secretions (opposite of beta2 stimulation in sympathetic)

who should not use muscarinic agonists

people with asthma and COPD

major symptoms of cholinergic crisis and AChEI poisoning

bronchospasm and increased bronchial secretions

ipratropium and tiotropium

muscarinic antagonists used to treat asthma and COPD

M3 stimulation in circular muscle (iris)

contraction→ miosis

miosis is a common symptom of…

opioid usage

M3 stimulation of circular ciliary muscle

contraction→ focus on near objects (accommodation)

tropicamide and cyclopentolate

muscarinic antagonists used to induce mydriasis and relaxation of iris. Will also cause cycloplegia (loss of near focus) for refraction testing

what happens in the pupil when M3 is stimulated to treat glaucoma?

contraction of circular muscle stretches iris away and opens up the angle for aqueous humour drainage. also causes miosis

what happens in the lens when M3 is stimulated to treat glaucoma?

contraction of longitudinal ciliary muscles stretches and opens trabecular meshwork to drain aqueous humour

pilocarpine

muscarinic agonist used to reduce intraocular pressure in glaucoma

What receptor is found in the heart

M2

muscarinic agonists in heart

decrease rate and force of contraction

atropine

muscarinic antagonist used to treat bradycardia

what receptor is found in the brain?

M1

what is cholinergic activity important for in the brain?

learning and memory

balance of ACh and dopamine

important for motor activities

why is tremor a common symptom of parkinsons

dopamine deficiency →too much ACh

what type of drug is used to treat parkinsons tremor

muscarinic antagonist

donepezil and rivastigmine

cholinergic agents (AChEIs that cross BBB) used to delay progression of alzheimers

trihexyphenidyl

muscarinic antagonist used to relieve tremor in parkinsons

what does activation of muscarinic receptors in the vestibular system cause

car sickness

scopolamine

muscarinic antagonist used to prevent motion sickness and PONV

side effects of muscarinic antagonists in brain

worsens alzheimers (memory loss)

what receptors are in endothelial cells

M3

activation of M3 in endothelial cells

nitric oxide production→ enters vascular smooth muscle→ muscle relaxation and vasodilation

muscarinic symptoms of cholinergic crisis

vomiting, miosis, tear production, salivation, sweating, diarrhea, urination, bradycardia, bronchospasm (all parasympathetic symptoms)

nicotinic symptoms of cholinergic crisis

skeletal muscle fasciculations and paralysis, respiratory paralysis

how to treat cholinergic crisis

atropine (antimuscarinic) and pralidoxime (reactivate AChE)

signs of atropine poisoning

dry mouth, blurry vision, dry eyes, urinary retention, constipation (parasympathetic functions lost) and CNS effects

physostigmine

drug used to treat atropine toxicity