Pharmacology Flashcards
What is the general function of muscarinic receptors? What type of stimulation do they receive?
cholinergic -> stimulate contraction of smooth muscle and increases gland secretion
Where are M2 and M3 receptors located? How does each of the work?
M2 - heart, nerves, smooth muscle -> inhibit adenylyl cyclase
M3 - glands, smooth muscle, endothelium -> activate phospholipase C, IP3, and DAG
What is the general function of alpha 1 adrenergic receptors? How does it work and what is the primary agonist?
- vasoconstriction and glandular secretion -> stimulates PLC, IP3, DAG, and intracellular Ca
- Epi main agonist
What is the general function of beta 2 adrenergic receptors? How does it work and what is the primary agonist?
- relaxes smooth muscle, vasodilation, bronchodilation -> stimulates adenylyl cyclase
- Ep main agonist
What catalyzes the synthesis of ACh? What 2 things combine to make ACh?
choline and Acetyl CoA make ACh using choline acetyltransferase (ChAT)
What stimulates the fusion of ACh vesicles w/ the synaptic cleft?
Ca entering the neuron
What influx occurs on the postsynaptic side of ACh binding to cholinergic receptors?
Na influx -> depolarization
What terminates ACh signaling and what is ACh cleaved into?
Acetylcholinesterase cleaves ACh into acetate and choline (choline recycled)
What is used to synthesize catecholamines?
tyrosine -> Dopa -> dopamine
What signals the release of catecholamines in the adrenal medulla?
presynaptic fiber releasing ACh to bind to nicotinic receptors on chromaffin cells
How do parasympathetics have a way to control smooth muscle of blood vessels? What triggers its release?
indirectly through NO released by endothelial cells after ACh binds to M3 receptors on endothelial cells
Which type of receptor is most dominantly located on vascular smooth muscle?
alpha 1
Name 5 reactions to the parasympathetic nervous system
- salivation, lacrimation
- pupil constriction
- decrease HR
- urination, dedication
- increased secretion and motility of GI tract
Name 5 reactions to the sympathetic nervous system
- cutaneous vasodilation
- pupil dilation
- increase HR
- reduced desire to urinate
- decreased secretion and motility of GI tract
Where do you generally find nicotinic receptors?
skeletal muscle and where presynapatic and postsynaptic fibers meet
What affect does activation of mAChRs have on the detrusor M. of the bladder?
contraction of detrusor -> urination
How does activation of the mAChRs cause trigone and sphincter relaxation if it is contracting the detrusor M.?
NO -> ACh binds to M3 receptors on endothelial cells which releases NO to relax the sphincters and allow urination
What type of effect is a muscarinic antagonist going to have on the GI system?
decrease parasympathetic activity -> constipation and dry mouth
What is a pheochromocytoma and where is it usually found?
adrenaline secreting tumor usually sitting in the adrenal medulla
What is tested in the urine to dx a pheochromocytoma and where does this come from?
metanephrine is tested in the urine -> byproduct of catecholamine metabolism
What receptors increase and decrease HR?
M2 - decrease HR
Beta 1 - increase HR
What would happen if you gave a beta-blocker to someone w/ a pheochromocytoma?
unopposed alpha stimulation -> catecholamines still being produced and can only bind to alpha receptors -> increased vasoconstriction and possible death
What is the location and function of alpha 2 receptors?
found presynaptically in the CNS; suppress further sympathetic activation when activated
Which group of receptors are most connected to the parasympathetic nervous system?
muscarinic receptors
Under what type of control are sweat glands? What type of receptor is responsible for sweat glands?
sympathetic -> muscarinic (not what you would normally think)
What would occur first if you ingested an AChE inhibitor in each of the following methods: ingestion, percutaneous absorption, lipid-soluble AChE inhibitors?
- ingestion: GI sx -> salivation, defecation, emesis
- percutaneous: localized sweating and muscle fasciculations
- lipid-soluble: CNS involvement very rapid (crosses blood brain barrier)
In what substances would you find AChE inhibitors?
organophosphates (insecticides)
Name 3 antidotes for organophosphate exposure
atropine (inhibit mAChRs), oxime (uncouple interaction between AChE and AChE inhibitor, benzodiazepine (alleviate convulsions)
What is myasthenia graves?
autoimmune disorder that decreases expression of nAChRs on skeletal muscle (causes muscle weakness)
What class of drug is used to treat myasthenia graves? What will this do to muscarinic receptors?
AChE inhibitor; will increase ACh at nicotinic and muscarinic receptors (cause adverse effects)
What can be given along with a AChE inhibitor to prevent adverse effects at muscarinic receptors?
muscarinic antagonist
