Cholinergic Mechanism Flashcards by Iseoluwa Ojo

Primarily, acetylcholine is associated with ____ neurons and the activation of ________.

motor

muscle function

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Nicotinic receptors function within the ___ nervous system and at the _______

While

muscarinic receptors function in _______ nervous systems, mediating innervation to __________

central; neuromuscular junction.

both the peripheral and central; visceral organs

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Nicotinic receptors are also used by PNS

T/F

Only CNS

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Choline esters (____,_____), which act at ___ sites, like acetylcholine, but are ____________

bethanechol, carbachol

all

resistant to degradation by acetylcholinesterases

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Mention 2 examples of choline esters?

Bethanecol

Carbachol

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Cholinomimetics ______________, esp. acetylcholine.

mimick the action of choline

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medications that directly act on muscarinic or nicotinic receptors are called _______________, because they mimic acetylcholine.
Examples of these medications include _____,_________ ,_______, and _______

direct cholinomimetics

bethanechol, carbachol, methacholine, and pilocarpine.

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Cholinesterase are chemicals that __________________.

breakdown the neurotransmitter acetylcholine

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Cholinesterase

This ____eases the amount of the acetylcholine or ________ in the synaptic cleft that can bind to muscarinic receptors, nicotinic receptors and others

Decr

butyrylcholine

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Anticholinesterase

Cholinesterase inhibitors, also known as anti-cholinesterase, are chemicals that ___________________. This ___eases the amount of the acetylcholine or butyrylcholine in the synaptic cleft that can bind to muscarinic receptors, nicotinic receptors and others

prevent the breakdown of the neurotransmitter acetylcholine or butyrylcholine

Incr

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Cholinergics
They are drugs that act on the _______,______, or _______

They ______ the effects that are mediated by acetylcholine

peripheral nervous system, central nervous system, or both.

enhance

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Cholinergics

Also known ______pathomimetic

parasym

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Cholinergics

It works in 2 ways;
1. Act ______ by _______ the effects of acetylcholine on acetylcholine receptors present in the body.
2. Act ________ by ____________________

Directly; enhancing

indirectly; inhibiting the enzyme that is responsible for the degradation of acetylcholine

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Types of anticholineesterases

Reversible –Bind to cholinesterase for a period of ______ to _____
Irreversible –Bind to cholinesterase and form a ________ –

minutes to hours

permanent covalent bond

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Drug Effects of Cholinergic Agonists

___eased gastric secretions
____eased gastrointestinal motility
____eased urinary frequency

Incr
Incr
Incr

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Drug Effects of Cholinergic Agonists

(Stimulate or Inhibit?) pupil Constriction (miosis)
(Increased or Reduced?) intraocular pressure
(Increased or decreased?) salivation and sweating

Stimulate

Reduced

Increased

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Drug Effects of Cholinergic Agonists

(Increased or Decreased?) heart rate

Causes (Vasodilation or Vasoconstriction?)

Decreased

Vasodilation

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It is important to know that:

At recommended low doses, the cholinergics primarily affect the ________ receptors.

At high doses, cholinergics stimulate the _______ receptors.

MUSCARINIC

NICOTINIC

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CNS excitation

High dose or low dose

High dose

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Ganglionic stimulation

High dose or low dose

High dose

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Adrenaline release

High dose or low dose

High dose

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RISE in BP

High dose or low dose

high dose

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Fall in BP

High dose or low dose

Low dose

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Increased GI motility

High dose or low dose

Low dose

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Bladder constriction High dose or low dose

Low dose

Salivation High dose or low dose

Low dose

Lacrimation High dose or low dose

Low dose

Bradycardia High dose or low dose

Low dose

Broncho Constriction High dose or low dose

Low dose

Examples of Cholinergic Agonist Examples of Direct-acting: ______,_____,____,____ Examples of In-direct-acting: _______,_____,______

acetylcholine, carbachol, pilocarpine Bethanechol physostigmine, pyridostigmine, donepezil (Aricept)

physostigmine Direct or indirect cholinergic agonist

Indirect cholinergic agonist

pyridostigmine Direct or indirect cholinergic agonist

Indirect cholinergic agonist

donepezil (Aricept) Direct or indirect cholinergic agonist

Indirect cholinergic agonist

carbachol Direct or indirect cholinergic agonist

Direct cholinergic agonist

pilocarpine Direct or indirect cholinergic agonist

Direct cholinergic agonist

Bethanechol Direct or indirect cholinergic agonist

Direct cholinergic agonist

Therapeutic Uses of Cholinergic Agonist Carbachol and pilocarpine are (direct or indirect?) acting cholinergic agonist Useful for _________ and _______

Direct glaucoma and intraocular pressure in surgery.

Bethanechol is a (direct or indirect?) acting cholinergic agonist that is used to ____ease _________ of _______ and ______. It (constricts or relaxes?) sphincters in _______ and ______, allowing them to _____.

Direct ; Incr ; Tone and motility bladder and GI tract Relaxes ; bladder and GI tract empty

Which is more important MUSCARINIC or Nicotinic

MUSCARINIC

Acetylcholine is used for treatment of: Myasthenia gravis ( _________) Alzheimer’s disease (________)

Pyridostigmine rivastigmine

Acetylcholine aids the action of muscle relaxants T/F

F It reverses it

Side effects of acetylcholine are: Ocular side effects: Corneal ______ Corneal ______ Corneal _______

swelling clouding decomposition

Side effects of acetylcholine are: Systemic side effects: _______ difficulty in _____ ____tension ______ (slow or fast?) heart rate

sweating Breathing Hypotension flushing Slow

Carbachol is primarily used in the treatment of _______, but it is also used during ________.

glaucoma ophthalmic surgery

Carbachol eyedrops are used to ___ease the _____ in the eye for people with glaucoma.

Decr pressure

Carbachol eyedrops is sometimes used to ______ the ____ during ______ surgery.

constrict; pupils cataract

Carbachol Is metabolized by plasma cholinesterases T/F

F Is not

Carbachol is selective T/F

F It’s not

Therapeutic uses of bethanechol include: _____eases _______ of ________ It relaxes __________ in _________, allowing them to empty

Incr; Tone and motility ; Bladder and GI tract sphincters in bladder and GI tract

Bethanecol Selective or not?

Selective

Bethanecol Is metabolized by plasma cholinesterases T/F

Structural differences between carbachol and Bethanecol?

Carbachol has an amide group only Bethanecol has an amide group and an ethyl

Therapeutic uses of Pilocarpine are: Pilocarpine is used to treat _______ caused by ______ in people with ___________ and to treat ______ in people with ________

dry mouth radiotherapy; head and neck cancer dry mouth Sjögren’s syndrome

Sjögren’s syndrome Is a condition that affects the _____ and causes _____ of certain parts of the body such as the ____________

immune system dryness eyes and mouth

Ophthalmic pilocarpine is used to treat _________, a condition in which increased pressure in the eye can lead to ____________.

glaucoma gradual loss of vision

Opthalmic Pilocarpine is in a class of medications called ______. It works by allowing ______ to _________.

miotics excess fluid drain from the eye

Structure of pilocarpine?

Has an imidazole attached to it

Indirect-Acting Agents Examples of Indirect-Acting Agents include: 1._________ 2. ________

physostigmine pyridostigmine

Therapeutic uses of physostigmine Physostigmine cause ___ muscle (contractions or relaxations?) Are used for treatment of _______ Are used to _________________ (antidote)

skeletal; contraction myasthenia gravis reverse anticholinergic poisoning

Indirect-Acting Agent—donepezil Used in the treatment of ____ to ____ ——- disease. Helps to increase ______ and ______

mild to moderate: Alzheimer’s memory and learning capabilities

Drug interactions Anti______ are known to antagonize cholinergic agents, resulting in decreased responses

histamines

Cholinergic Antagonist They are drugs that compete with acetylcholine" for its binding sites at synaptic junctions thereby inhibiting its activity and preventing the transmission of _______pathetic nerve impulses.

parasym

Depending on the type of receptor to act on, cholinergic antagonists are either classified as ________ or ______

muscarinic antagonists or nicotinic antagonists.

Mechanism of Action of Cholinergic Antagonists  Block ACh at the _____ receptors in the PNS prevent ACh from ______ Once these drugs bind to receptors, they inhibit nerve transmission at these receptors.

muscarinic binding to the receptor site.

Cholinergic Antagonist are: Natural group of ______ found in _____ (_______) 1. ____ 2. _______

alkaloids; plants BELLADONA ALKALOIDS Atropine Scopolamine

Atropine (________/ _____) Scopolamine ( ____ pills causing ______.

properative; antidote Sleeping; drowsiness

Drug Effects of Cholinergic Antagonist Small doses: ___ease heart rate. Large doses: ___ease heart rate . Small doses: ____ease tremors. Large doses: _____,_____,______ pupils

Decr Incr Decr drowsiness, hallucinations. Dilated

Dilated pupils aka ?

mydriasis

Drug Effects of Cholinergic Antagonist ____ease gastric secretion. ___ease motility and peristalsis. ____eased constriction of internal sphincter causing urinary retention ____eased salivation, sweating. ____eased bronchial secretions

Decr Decr Incr Decr Decr

Therapeutic Uses of Cholinergic Antagonists It is used in treatment of _______ disease by decreasing _____ and _______ Low doses:___ the heart rate. High doses: ______ heart rate

Parkinson’s muscle rigidity and power tremors. slow; increased

Therapeutic Uses of Cholinergic Antagonists Atropine Used primarily for _____ disorders ________ disease. ________ disease. _________ states

cardiovascular Peptic ulcer Irritable bowel GI hypersecretory

Cholinergic agonists are used to Used to treat Chronic bronchitis and Asthma T/F

F It’s cholinergic antagonists Used to treat Chronic bronchitis and Asthma

Side effects at cholinergic antagonists ________ _________ _________ _____eased salivation ____eased sweating ____eased bronchial secretions

Irritability disorientation halucination Decr Decr Decr

Structure of acetylcholine can be divided into 3 parts Name them

Acyl group Ethylene bridge Onium group

Side Effects of Indirect cholinomimetics ____cardia, ___tension, _____ abnormalities ___,___,______ Abdominal _____, ___eased secretions, nausea, vomiting

Bradycardia; hypotension; conduction Headache, dizziness, convulsions cramps Incr

Side Effects of Indirect cholinomimetics ____eased bronchial secretions ____eased Lacrimation, sweating, salivation Loss of binocular ______

Incr Incr accommodation

Ganglionic stimulants Is predominantly on SYMP in what and what ?

Blood vessels Sweat glands

Ganglionic blockade Is predominantly on SYMP in what and what ?

Blood vessels

Acetylcholine has 3 parts in its structure Mention them

Acyl group Ethylene bridge Onium group

Modifications in Acyl group(Ch3-COO) of acetylcholine If the methyl group is substituted with ______, it results in ______ compound If the ester group is substituted for ____ or ____, _____ compound is formed

Primary amine; more potent Ether; ketone group; more potent

Modifications in ethylene bridge(Ch2-Ch2) of acetylcholine Replacement of hydrogens in methyl group with ______ leads to ______ cholinergic activity. But replacing with a larger group than methyl leads to a _____ in activity Substitution of methyl group at ____ carbon acts (selectively or non-selectively?) on _______ receptors

methyl group equal or greater ; decrease beta; selectively MUSCARINIC

Modifications in Onium group (N-Ch3-Ch3-Ch3) of acetylcholine If methyl group is replaced by ———- or ______ group it produces (active or inactive?) compounds

ethyl group or larger alkyl inactive

Which amines is more active? Pry,sec, tert Or Quaternary

Quaternary